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FUR DYEING AND FUR DRESSING 



PEINCIPLES AND PRACTICE 



OF 



FUE DKESSING AND FUR DYEING 



BY 



WILLIAM E. AUSTIN, B.S. 

CONSULTING CHEMIST TO THE FUR INDUSTRY 



ILLUSTRATED 




\^^'i .-^. 



NEW YORK 
D. VAN NOSTRAND COMPANY 

Eight Warren Street 
1922 



\o'* 






Copyright, 1922, by 
D. VAN NOSTRAND COMPANY 



All rights reserved, including that of translation into 
foreign languages, including the Scandinavian 



. n i 



i^^' 



RUG 12 22 



PRINTED IN THE UNITED STATES OF AMERICA 



©CI.A677834 



PREFACE 

THE great increase in the use of furs during the past 
few decades has caused the fur dressing and dye- 
ing industry to rise from relative insignificance 
to considerable importance as a branch of applied chemistry. 
The past eight years, moreover, have witnessed the virtual 
transference of the leadership in the dressing and dyeing of 
furs from Europe to America, and in the quality and variety 
of products, the domestic industry is now in every way the 
equal of, and in many respects superior to the foreign. The 
great bulk of American furs which formerly were sent to 
Leipzig, Paris or London to be dressed and dyed, are now 
being dressed and dyed in this country. 

In spite of these facts, very little is generally known about 
the nature and manner of the work constituting the dress- 
ing and dyeing of furs. Even among members of other 
branches of the fur trade, there is very little accurate in- 
formation on the subject. Real knowledge concerning fur 
dressing and dyeing is possessed only by those actually en- 
gaged in the industry. The interest and efforts of scientists 
and technologists have been enlisted to only a small extent 
in the technical development of the industry. The reason 
for this may be attributed to two related causes: first, the 
almost monastic seclusion in which fur dressers and dyers, 
particularly the latter, conducted their operations, and even 
to-day the heavy cloud of mystery is being dispelled but 
very slowly; and second, as a consequence of the first, the 
lack of any reliable literature on the subject. Of the few 
books which have been written on the industry of fur dress- 
ing and fur dyeing (all of them either German or French), 
most are hopelessly out of date, or contain no trustworthy 
data; or, if they do have real merit, they cannot be obtained. 

iii 



PREFACE 



Numerous articles in the technical journals are of interest, 
but they contain very little information of value. 

This work is intended for a two-fold purpose: first, that 
it may serve as a text-book for those who expect to make 
fur dressing and dyeing their vocation. The fundamental 
principles upon which the industry is based are discussed in 
the light of the most recent chemical and technical develop- 
ments, and the most important operations are treated fully 
and systematically, and are illustrated with practical 
examples. 

Secondly, as a practical handbook for the worker in the 
fur dressing and dyeing plant. The latest factory processes 
and methods are described, and numerous working formulas 
given. The formulas are all such as have been successfully 
used on a large scale, and give satisfactory results when 
applied under the proper conditions. 

In addition, it is believed that the book will prove of 
interest to chemists and other students of industrial chemis- 
try, since it will be an introduction into a field of applied 
chemistry, about which very little is known to those out- 
side of the industry. 

Thanks are due to Dr. L. A. Hausman, of Cornell Univer- 
sity, for material used in Chapter II; to Dr. E. Lesser of 
the American Dyewood Company, for information and 
assistance on the subject of Vegetable Dyes ; to the Gaskill 
Chemical Corp., American Aniline Products, Inc., the 
Cassella Company, and the Franklin Import <fe Export Co., 
for information about their products in connection with the 
chapter on Oxidation Colors; to F. Blattner, Fletcher Works, 
Inc., S. M. Jacoby Co., Proctor & Schwartz, Inc., Reliable 
Machine Works, Seneca Machine & Tool Co., Inc., and the 
Turner Tanning Machinery Co., for the use of the cuts of 
the various machines. 

William E, Austin. 

New York, May. 1922. 



IV 



TABLE OF CONTENTS 

chapter page 

Preface 

I. Furs and Their Characteristics 1 

Introductory. Knowledge of furs essential. Definitions. 
Differences in furs of various animals. Effect of climate on 
furs. Effect of age and season on furs. Durability and rela- 
tive weights of furs. Description of important furs. 

II. Structure of Fur 21 

The skin. The hair. Under-hair and top-hair. Chemical 
composition of furs. Action of chemicals on the skin. Action 
of chemicals on the hair. 

III. Fur Dressing: Introductory and Historical . 29 

Objects of fur dressing. Origin of fur dressing. Use of fats. 
Use of salt and alum. Use of the tannins. Early organiza- 
tions of the fur workers. Modern organizations of the fur 
dressing industry. 

IV. Fur Dressing: Preliminary Operations 36 

Flat skins and cased skins. Herbivorous and carnivorous 
fur animals. Beaming or scraping. Softening the skins. 
Cleaning; hydro-extracting. Fleshing. 

V. Fur Dressing: Tanning Methods 45 

Nature of the tanning process. Chief tanning methods. 
Comparison of the tanning methods. Effect of dyeing opera- 
tions on the dressing. 

VI. Fur Dressing: Drying and Finishing 71 

Importance of the drying process. Methods of drying. A 
modern type of drying device. Oiling. Staking or stretching. 
Beating and combing. Drum-cleaning. Unhairing and 
shearing. 

VII. Water in Fur Dressing and Dyeing 85 

Importance of water in dressing and dyeing. Water suitable 
for dressing and dyeing. Soft water and hard water. Effects 
of hardness in water. 

VIII. Fur Dyeing: Introductory and Historical... 90 

Purposes of fur dyeing. Improvement of furs faulty in 
color. Production of a uniform shade on furs. Dyeing furs 
to obtain novel effects. Imitation of valuable furs on cheaper 
skins. Difficulties due to the hair. Difficulties due to the 
leather. 

V 



TABLE OF CONTENTS 



CHAPTER PAGE 

IX. Fur Dyeing: General Methods 98 

Two methods of dyeing furs. Development of the dyeing 
methods. The brush process. The dip process. Blending. 
Drying and finishing the dyed furs. 

X. Fur Dyeing: Killing the Furs 106 

Nature of the killing process. Old killing formulas. 
Modern killing agents. Procedure of killing. Killing with 
soda. Kilhng with lime. Killing with caustic soda. 

XI. Fur Dyeing: Mordants 114 

Nature of mordanting. Purposes of mordanting. Theory 
of mordants. Procedure of mordanting. Aluminum mor- 
dants. Iron mordants. Copper mordants. Chromium mor- 
dants. Tin mordants. Alkaline mordants. 

XII. Fur Dyeing: Mineral Colors Used On Furs . 125 
Mineral chemicals as fur dyes. Lead dyes. Potassium 
permanganate as a dye. Other mineral dyes. 

XIII. Fur Dyeing: Vegetable Dyes 128 

Wood dyes. Old dye formulas. The vegetable dye mate- 
rials. The tannin substances. Logwood. Fustic. Brazil- 
wood. Other vegetable dyes. Characteristics of the wood 
dyes. Application of the vegetable dyes. Application by the 
brush process. Application bj^ the dip process. Production 
of shades other than black. 

XIV. Fur Dyeing: Aniline Black 144 

Dyeing of seal. Nature and history of Aniline Black. 
Chemistry of the Aniline Black process. Three stages in the 
formation of Aniline Black. Methods of applying Aniline 
Black. One-bath Aniline Black. Oxidation Aniline Black. 
Diphenyl Black. Aniline Black by Green's process. Aniline 
Black by the dip method. 

XV. Fur Dyeing: Oxidation Colors 155 

The original patents. The first Oxidation fur dyes. Early 
difficulties. Solution of the difficulties. Progress with the 
Oxidation dyes. Para-phenylene-diamine : a typical Oxida- 
tion color. Range of shades obtainable. Mordants. Pro- 
cedure in dyeing. Typical formulas. Combination of 
Oxidation colors with other dyes. 

XVI. Fur Dyeing: Coal Tar Dyes 171 

Use of coal tar dyes. Basic colors. Acid colors; dyeing at 
higher temperatures. Chrome colors. Vat dyes. 

XVII. Bleaching of Furs 179 

Purpose of bleaching. Steps in the bleaching process. 
Methods of bleaching. Bleaching materials with reducing 
action. Bleaching materials with oxidizing action. Blueing. 

Bibliography 185 

vi 



FUR DRESSING AND 
FUR DYEING 

CHAPTER I 
FURS AND THEIR CHARACTERISTICS 

FURS have in general two uses: as the goods which 
constitute the basis of the furrier's art, and as the 
source of material for the hat manufacturer. In the 
latter case, only the hair part of the fur is utilized in the 
hat trade for the production of felt, the skin being either 
made into leather, or used as the raw material for making 
high-grade glue and gelatine. It is the furrier, therefore, 
who uses the great bulk of furs, aiid requires them to be 
dressed and dyed. 

In discussing the dressing and the dyeing of furs, there 
are, broadly speaking, two fundamental subjects to be con- 
sidered: first, the raw materials employed, which are, of 
course, the skins or pelts as they come from the trapper. 
(Other substances used in fur dressing and dyeing are acces- 
sories, and will be studied in connection with the processes.) 
Second, all those operations, physical and chemical, manual 
and mechanical, to which the raw skins have to be sub- 
jected in order to obtain the finished fur, ready for use by 
the furrier. 

Next to the inherent qualities of the fur skin, the future 
value of a fur in a manufactured garment depends largely 
on the dressing and dyeing it receives. It is in these opera- 
tions that the beauty of the fur can be brought out to its 
fullest degree, and if possible, enhanced, or the attractive 
features can be marred or destroyed, and the fur rendered 
quite worthless. Therefore, it is cjuite essential for the fur 



FUR DRESSING AND FUR DYEING 

dresser and the fur dyer in addition to the technical knowl- 
edge and experience which are the fundamental requisites 
of the industry, also to have more than a superficial famil- 
iarity with the various kinds of furs. In fact, an accurate 
knowledge of the nature and chief characteristics of furs in 
general, and of the individual classes, in particular, is al- 
most indispensable to obtain the best results. The habits 
and habitats of the various fur-bearing animals are factors 
which largely determine the constitution of the fur, and 
the nature of the skin. There are as many different kinds 
of fur hair, with as many different kinds of skin bearing the 
hair, as there are classes of furs. The methods of dressing, 
and often, if the furs are to be dyed, the manner of dyeing, 
are determined by the nature of these component parts of 
furs. Various chemicals affect furs in widely different ways. 
The divergence with regard to the physical and chemical 
properties of the classes of furs is such as to make almost 
imperative a detailed knowledge of the typical members of 
the many groups of commercial furs. 

To be sure, there are many engaged in the dressing and 
dyeing of furs, who never made a formal study of this phase 
of the industry, but acquired their knowledge empirically, 
and are apparently quite successful. It must not be denied, 
that practise and experience, as in every field of enterprise, 
are essential to obtaining the best results. But the time and 
cost of acquiring this precious experience can be consider- 
ably reduced by systematically studying the important 
characteristics and properties of furs. These will be treated 
briefly, but in sufficient detail to form a basis for discussing 
the operations of ch^essing and dyeing. 

Fur-bearing animals are mammals whose skins are used 
in the manufacture of fur garments and other fur wearing 
apparel. The skin, when it is removed from the animal is 
called a pelt, or sometimes, in the case of large animals, a 
hide. The pelt, after having been dressed and dyed, is 
called a fur, the skin part being referred to as the leather, 



FURS AND THEIR CHARACTERISTICS 

and the hair as the pelage. However, this terminology is 
not strictly adhered to in practise, and the various terms are 
often employed interchangeably. 

The various fur-bearing animals differ considerably in the 
characteristics of the furs they yield. With few exceptions, 
notably beaver and Alaska red fox, the depth of shade in- 
creases as the habitat of the animal species is nearer the 
equatorial regions. There seems to be a direct relationship 
between the intensity of color of the pelt, and the distance 
from, or proximity to the polar, or the torrid regions. Thus, 
white mammals, such as polar bear, ermine, white or Si- 
berian hare, are found only in the northern lands. An ex- 
ception is the sheep, which, due to its domestic nature, can 
be found in almost all parts of the civilized world. Tropical 
animals on transportation to colder climates, have been 
known to become lighter-haired when adapted to their new 
environment. The skins of animals living in dense woods 
or forests, are generally of a deeper color than in animals 
living in more open territory. As a general rule, fur-bearing 
animals have darker hair on the back than on the sides and 
belly. The badger, hamster, ratel and panda are exceptions 
having the darker hair on the belly and sides, and the lighter 
hair on the back. With regard to the intensity of color, the 
skunk has the blackest fur, although some domestic cats 
are also quite black. Other animals whose fur is nearly 
black, are the black bear, and the black fox, which is a 
variety of the silver fox, but the color is often of a brownish 
shade. The colors which predominate among animals 
of the fur-bearing variety, are white, black, brown, and 
grey. Less common are yellow shades, and those known as 
blue. 

The quality of the fur on all mammals improves with cold, 
and animals living at greater altitudes, with correspond- 
ingly lower temperatures, have thicker and finer hair than 
those living nearer sea-level. A cold winter generally pro- 
duces fur of high quality and fine color, a mild winter may 



FUR DRESSING AND FUR DYEING 

cause the hair to be inferior. In all climates, animals found 
in dense woods, have fur which is deeper, silkier, thicker, 
and glossier than that of animals living in the open. Ani- 
mals inhabiting inland lakes and rivers, have finer and softer 
hair than those living near the coast or land exposed to sea 
winds. In general, the hair of animals of the cold regions 
is short, fine, soft, and downy, while the hair of animals of 
warmer lands, is longer, stiffer, and harder. 

Both the quality and color of the fur vary with the age 
of the animal. The young usually have a thicker coat of fur 
than adults, but the hair is too soft, and the skin generally 
too tender to be fit for use. In certain cases, particularly 
the baby lambs, very young skins are especially prized, and 
eagerly sought, but extraordinary care has to be exercised in 
working with them. Fur is at its best when the animal is 
between one and two years old. After this age, the fur be- 
comes coarse and scraggy. The animal attains its fullest 
growth of hair usually in the height of winter, and the fur 
is best between then and very early spring. Before mid- 
winter the hair is short and thin, and in the spring it be- 
gins to shed, and will continue to fall out even in the dressed 
fur. The color of the hair also becomes lighter with age, 
and the new growth which generally comes in the fall is 
darker than the old coat. 

Different members of the same species, will, other factors 
such as age and season being equal, vary as to color and 
quality. There may even be several different color phases 
of the same species of animal, such as the cross fox and the 
silver fox, both of which are of the same genus as the red 
fox; black muskrats are of the same class as the brown 
variety, etc. The individual pelt likewise presents many 
variations in color and nature of the hair. In some parts, 
the hair is thicker and softer than others, and the color 
varies in intensity and shade throughout the different sec- 
tions of the skin. 

Furs do not have chfferences confined to the hair part 



FURS AND THEIR CHARACTERISTICS 



only; the leather also presents considerable variation 
among the different fur-bearing animals, especially in re- 
gard to the weight and thickness. The durability of furs, 
relatively considered under similar conditions of wear, also 
varies widely. In the following table the relative durability 
of dressed furs, and in certain instances also dyed furs, otter 
being taken as standard, is given, as well as the weight in 
ounces per square foot of skin of these furs. 

Name of Fur Durability Wt. in oz. 

Otter = 100 per sq. jt. 

Astrachan 10 3 

Bear, brown or black 94 7 

Beaver, natural 90 4 

Beaver, plucked 85 3% 

Chinchilla 15 IVa 

Civet cat 40 2% 

Coney 20 3 

Ermine 25 VA 

Fox, natural 40 3 

Fox, dyed black 25 3 

Genet 35 2% 

Goat 15 41/8 

Hare . / 05 2V4 

Krimmer 60 3 

Kolinsky 25 3 

Leopard 75 4 

Lynx 25 2% 

Marten, Baum natural 65 2% 

Marten, Baum blended 45 2-% 

Marten, Stone natural 45 2% 

Marten, Stone dyed 35 2% 

Mink, natural 70 3Vi 

Mink, dyed 35 SVi 

Mink, Jap 20 3 

Mole 07 1% 

Muskrat 45 3^/4 

Nutria, plucked 25 3Vi 

Opossum, natural 37 3 

Opossum, dyed 20 3 

Opossum, Australian 40 3V2 

Otter, land 100 iV2 

Otter, sea 100 41/2 

Persian lamb 65 3H 

5 



FUR DRESSING AND FUR DYEING 

Name of Fur Durability Wt. in oz. 

Otter = 100 per sq. jt. 

Pony, Russian 35 ZV2 

Rabbit 05 2Vi 

Raccoon, natural 65 2^/4 

Raccoon, dyed 50 2% 

Sable 60 21/2 

Sable, blended 45 21/2 

Seal, fur 80 31/2 

Seal, fur dyed 70 ZVs 

Skunk, tipped 50 2% 

Squirrel, grey 20-25 1% 

Wolf, natural 50 61/2 

Wolverine 100 7 

In estimating the value of a fur, many factors have to 
be considered. There is no one standard by which the 
skins are judged, each kind of fur having its own criterion. 
However, the general points by which raw furs are graded 
are, color, size, origin, quality and quantity of hair, con- 
dition of leather, date or season of trapping, methods of 
handling, etc. Beaver, for example, is graded as large, 
medium, small and cubs. Red foxes, first, into Alaska, 
Labrador, and Nova Scotia, and then these divisions are 
classed as large, medium and small. Skunks are graded 
according to the amount of white on the skin, the less white, 
the more valuable the fur. 

The qualities which make a fur desired depend first of 
all on the nature of the fur itself. Pretty color, luster, 
thickness, softness, length, uniformity and regular fall of 
the hair are the chief points to be considered. While 
the leather part of the fur is of secondary importance 
in the evaluation of a fur, it must possess strength, light- 
ness of weight, and when properly dressed, should be supple 
and have a certain firmness or ' feel.' The abundance or 
scarcity of a fur-bearing animal also determines the value 
of the fur. Furs which are always comparatively rare, 
such as silver fox, Russian sable, chinchilla, etc., are always 
highly prized. In this connection, circumstances which 

6 



FURS AND THEIR CHARACTERISTICS 

tend to decrease the number of available pelts of any par- 
ticular animal, such as pestilences, gradual extermination 
due to excessive trapping, prevention of trapping, by pro- 
tective laws, also affect the value of a fur. A third factor 
which has an influence on the value of furs, is the prevailing 
style or fashion. Many kinds of furs which are both beauti- 
ful and rare, such as Russian sable or chinchilla, are prac- 
tically unaffected by the whims of fashion. But a fur of 
ordinary value may at times become so popular, that the 
demand for it will cause its price to be greatly increased. 
Similarly, a fur which has enjoyed a considerable vogue, 
may pass out of demand for a time and consequently depre- 
ciate in value. 

A detailed description of the various furs used in com- 
merce is not within the scope of this work, because such 
an account rightly belongs in a book on zoology. However, 
it is desirable that the reader who is interested in the dress- 
ing and dyeing of furs should have at least a passing ac- 
quaintance with the chief furs used in commerce, together 
with such of their individual characteristics as are of im- 
portance. The figures given are for the average dressed 
skin.^ 

Astrachan, see Lambs. 

Badger. — 2x1 ft. This is one of the few animals 
whose fur is darker on the belly than on the back. The 
American sorts have coarse, thick under-hair of a pale fawn 
or stone color, with a growth of longer black and white hairs 
3-4 inches long. The Japanese varieties are usually dyed for 
imitation skunk. The American kind is also dyed occasion- 
ally but is mostly used natural. Badger hair is very exten- 
sively used for ' pointing.' 

Bear, Black. — 6x3 ft. Has fine, dark brown under- 
hair, with bright, flowing black top-hair 4 inches long. The 
fur of cubs is nearly as long, although the skins are much 

1 Descriptions after W. S. Parker, Deputy Chairman, Fur Section ot 
London Chamber of Commerce, in Enclyclopedia Britannica, 11th Ed. 



FUR DRESSING AND FUR DYEING 

smaller, and the hair is finer, softer, and lighter-pelted. The 
best skins are from Canada. 

Bear, Brown. — 6 x 3 ft. Similar to the Black Bear, but 
more limited in number. The color ranges from a light yel- 
low to a rich dark brown. The best and most valuable sorts 
come from the Hudson Bay territory, inferior skins coming 
from Europe and Asia. 

Bear, White. — 10 x 5 ft. This is the largest of the 
bears. The hair is short and close except on the flanks, 
while the color ranges from white to yellow. The best skins 
come from Greenland, the whitest being the most valuable. 

Beaver. — 3x2 ft. This is the largest of the rodents, 
and is very widely used; formerly to a great extent in the 
hat trade. The under-hair is close and of a bluish-brown 
hue, and nearly an inch deep. The over-hair is coarse, 
bright black or reddish-brown in color, and is usually 
plucked out, as the under-hair is the attractive part of the 
fur. The darkest skins are the most valuable. Formerly 
beaver was used to dye in imitation of seal, but more suit- 
able furs are now used. 

Broadtail, see Lambs. 

Caracul, see Lambs. 

Cat, Civet. — 9X4^ inches, with short, thick and dark 
under-hair, and silky, black top-hair with irregular white 
markings. It is similar to the skunk, but is lighter, softer, 
less full, and has no disagreeable odor. 

Cat, House. — 18 x 9 inches. Is mostly black and dark 
brown, the best skins coming from Holland. The hair is 
weak, coming out with the friction of wear. In the trade, 
the black variety is known as genet. 

Chinchilla. — 12 X 7 inches. This is one of the rarest 
and most beautiful furs. It comes from Bolivia and Peru, 
where, due to the uncontrolled trapping of the animal, 
it is becoming scarce, and this compelled the governments 
to enact laws prohibiting the taking of chinchilla for a cer- 
tain period. The fur is of a delicate blue-grey, with black 

8 



FURS AND THEIR CHARACTERISTICS 

shadings, the fur being l-l-j inches deep. Unfortunately, 
the skin is quite perishable. 

Chinchilla, La Plata. — 9x4 inches. Incorrectly called 
" bastard chinchilla " in the trade. It is a similar species 
to the Bolivian chinchilla, but due to the lower altitude and 
warmer climate of its habitat, is smaller, with shorter and 
less pretty hair, the color of the under-hair being darker, 
and of the top-hair less pure. It is quite as undurable as 
true chinchilla. 

Chinchillone. — 13 x 8 inches. Is also from South 
America. The fur is longer, weaker, poorer and yellower 
than real chinchilla, but the skins are often dyed in shades 
closely resembling the natural chinchilla. 

Ermine. — 12 X 21 inches. The under-hair is short and 
even, with the top-hair slightly longer. The leather is light, 
close in texture, and quite durable. In mid-winter the color 
is pure white, except the tip of the tail, which is usually 
quite black. The best skins are from Siberia, 

Fisher. — 30 X 12 inches, with tail 12-18 inches long. It 
is the largest of the marten family. The under-hair is deep, 
and of a dark shade, with a fine dark, glossy and strong top- 
hair, 2 or more inches long. The best skins are from Canada. 
The fur is something like a dark silky raccoon, while the tail, 
which is very highly prized, is almost black. 

Fitch. — 12 X 3 inches. It is of the marten species, and 
its common name is polecat. The under-hair is yellow and 
^ of an inch deep. The top-hair is black, H-lf inches long, 
very fine and open in growth, and not so close as the mar- 
tens. The largest and best skins are from Denmark, Hol- 
land and Germany. The Russian skins are smaller, silkier, 
and are usually dyed as a substitute for sable. 

Fox, Blue. — 24 X 8 inches. The under-hair is thick and 
long, while the top-hair is fine and not so plentiful as in 
other foxes. It is foimd in Alaska, Hudson Bay Territory, 
Greenland and Archangel. Although called blue, the color 
is really of a slaty or drab shade. The skins from Archangel 

9 



FUR DRESSING AND FUR DYEING 

are more silky and of a smoky bluish color, and being scarce 
are most valuable. The white foxes which are dyed a smoky 
blue are brilliant and quite unlike the browner shades of the 
blue-fox. 

Fox, Cross. — 20 X 7 inches. The skins generally have a 
pale yellow or orange tone, with some silver points, and a 
darkish cross marking on the shoulders, on account of which 
the animal got its name. Some are very similar to the pale 
red foxes of Northwest America. The darkest and best 
skins are from Labrador and Hudson Bay, those from 
lower latitudes being inferior. 

Fox, Grey. — 27 X 10 inches. Has a close dark drab 
under-hair, with coarse regular, yellowish, grizzly-grey top- 
hair. The majority of the skins come from Virginia and 
southwestern U. S. A. Those from the west are larger and 
brighter-toned. 

Fox, Kit. — 20 X 6 inches. The under-hair is short and 
soft, as is also the top-hair, which is a very pale grey mixed 
with some yellowish-white hairs. It is the smallest of the 
foxes, and is found in Canada and northern United States. 

Fox, Red. — 24 X 8 inches, although some kinds are 
larger. The under-hair is long and soft, and the top-hair 
is plentiful and strong. The colors range from pale yellow 
to a dark red, some being very brilliant. It is widely found 
in northern America, China, Japan, and Australia. The 
Kamchatka foxes are exceptionally fine and rich in quality. 
Farther north, near the open sea, the fur is coarse. The 
skins have an extensive use, both natural and dyed. They 
are dyed black in imitation of the black fox, or these when 
pointed with badger or other white hair to imitate the silver 
fox. 

Fox, Silver. — 30 X 10 inches. The under-hair is close 
and fine, and the top-hair, which is black to silvery, is 3 
inches long. The fur on the neck usually runs almost black, 
and in some cases the black extends over half the length 
of the skin. When all black, it is a natural black fox, and 

10 



FURS AND THEIR CHARACTERISTICS 



is exceedingly rare and high-priced. The silver fox is very 
valuable, the finest wild skins coming from Labrador. The 
tail is always tipped white. The majority of the silver fox 
pelts that reach the market today are bred on ranches in 
Canada and the United States. 

Fox, White. — 20 x 7 inches. It is usually small and in- 
habits the extreme northern sections of Hudson Bay, Labra- 
dor, Greenland, and Siberia. The Canadian are silky-haired 
and inclined to a creamy color, while the Siberian are whiter 
and more woolly. The under-hair is generally of a bluish- 
grey tone, but the top-hair in winter is usually full enough 
to hide such a variation. Those skins which have under-hair 
that is quite white are rare and much more expensive than 
the others. In summer specimens of these species have 
slightly discolored coats, the shades resembling those of the 
blue fox. The skins which are not perfectly white are 
bleached, or if they cannot be bleached sufficiently white 
they are dyed various shades of smoke color, blue-greys and 
also imitation blue fox. 

Goat. — The size varies greatly. The European, Arabian 
and East Indian varieties are used mainly for leather and 
wool. Many from Russia are dyed black for rugs. The 
hair is brittle, with poor under-hair, and is not durable. The 
Chinese export many skins in grey, black and white, made 
into rugs of two skins each. Frequently the skins are dyed 
black or brown in imitation of bear. 

Hamster. — 8 X 31 inches. A destructive rodent found 
largely in Russia and Germany. The fur is very flat and 
poor, of a yellowish-brown color, with a little marking of 
black. On account of its lightness it is used for linings ; oc- 
casionally it is dyed. 

Hare. — 24 X 9 inches. The common hare of Europe is 
used mostly for the hatters' trade. The white hares of 
Russia, Siberia, and other northern regions are the ones 
mainly used for furs. It is whitest in mid-winter, and the 
fur on the flanks is longer than that on the back. The hair is 

11 



FUR DRESSING AND FUR DYEING 

brittle and not durable, and the leather is quite as bad. Yet 
the skins are used to dye imitations of more than a dozen 
different furs. The North American hares are also dyed 
black and brown. 

Kangaroo. — The sizes vary greatly, the larger kinds be- 
ing generally used for making leather. The sorts used for 
fur are, blue kangaroo, bush kangaroo, wallaroo, rock 
wallaby, swamp wallaby, and short-tailed wallaby. Many 
of the swamp wallabies are dyed imitation skunk, and look 
quite attractive. The colors are generally yellowish or 
brown, some in the swamp variety being dark brown. The 
skins are quite strong. The rock wallabies are soft and 
woolly, and often have a bluish tone. They are used for 
rugs. 

Kolinsky. — 12 x 2^ inches. It is of the marten family. 
The under-hair is short and rather weak, but regular, as is 
also the top-hair. The color is usually a uniform yellow. 
They are generally dyed in imitation of other members of 
the marten family. It is very light in weight, and the best 
skins are obtained from Siberia. The tails are used for 
artists' " sable " brushes. 

Lambs. — Those of commercial interest are from South 
Russia, Persia, and Afghanistan, and include Persian Lamb, 
Broadtail, Astrachan, Shiraz, Bokhara, Caracul, and 
Krimmers. 

The Persians are 18 x 9 inches, and are the finest and 
best. When properly dressed and dyed they should have 
regular, close, bright curls, varying from small to very large 
and if of equal size, regularity, tightness and brightness, 
their value is inestimable. 

All the above lambs, except krimmer, are naturally a 
rusty black or brown, and are in most cases dyed a jet black. 
Luster cannot be imparted where naturally lacking. 

Broadtails, 10 x 5 inches, are the young of the Persians, 
killed before the wool has had time to develop beyond the 
flat wavy state. They are naturally of exceedingly light 

12 



FURS AND THEIR CHARACTERISTICS 

weight, and when of an even pattern possessing a lustrous 
sheen are costly. The pelt, however, is too delicate to resist 
hard wear. 

Astrachan, Shiraz, and Bokhara lambs, 22 x 9 inches, 
are of a coarser and looser curl. Caracul lambs are the very 
young of the astrachan, and the finest skins are almost as 
effective as the broadtails, although not so fine in texture. 

Krimmers, 24 x 10 inches are grey lambs obtained from 
Crimea. They are of a similar nature to the caraculs, but 
looser in curl, and ranging in color from a very light to a 
dark grey, the best being pale bluish-greys. 

Slink lambs come from South America and China. The 
South American are very small, and generally those are 
still-born. They have a particularly thin pelt, with very 
close. wool of minute curls. The Chinese sorts are much 
larger. 

Leopard. — 3x6 feet long. There are several kinds, the 
chief being the snow leopard or ounce, Chinese, Bengal, Per- 
sian, East Indian, and African. The first variety inhabits 
the Himalayas, and has a deep, soft fur, quite long as com- 
pared with the Bengal sort. The colors are pale orange and 
white with dark markings. The Chinese are of a mechum 
orange-brown color and full in fur. The East Indian are less 
full and not so dark; the Bengal are dark and medium in 
color with short, hard hair. The African are small, with 
pale lemon-colored ground, and very closely marked with 
black spots. 

Lynx. — 45 X 20 inches. The under-hair is thinner than 
in the fox, but the top-hair is fine, silky and flowing, 4 inches 
long, of a pale grey, slightly mottled with fine streaks and 
dark spots. The fur on the flank is longer, and white, with 
very pronounced markings of dark spots, and this part of 
the skin is generally worked separately. Skins with a bluish 
tone are more valuable than those with a sandy or reddish 
hue. The lynx inhabits North America as far south as 
California. The best skins come from Hudson Bay, and also 

13 



FUR DRESSING AND FUR DYEING 

Sweden. They are generally dyed black or brown, similar 
to dyed fox. 

Marmot. — 18 x 12 inches. A rodent found largely in 
the south of Germany. The fur is yellowish-brown, rather 
harsh and brittle, and without under-hair. Also found in 
North America, China, and the best skins come from Russia. 
It is dyed brown in imitation of mink or sable, the stripes 
usually being put on in the completed garment. 

Marten, Baum. — 16 x 5 inches. Also called Pine 
Marten, and is found in the woods and mountains of Russia, 
Norway, Germany and Switzerland. It has a thick under- 
hair with strong top-hair, and ranges from a pale to a dark 
bluish-brown. The best are from Norway, are very durable 
and of good appearance, and a good substitute for the 
American sable. 

Marten, Japanese. — 16x5 inches. It is of a woolly na- 
ture with rather coarse top-hair, and quite yellow in color. 
It is dyed, but it is not an attractive fur, lacking a silky, 
bright and fresh appearance. 

Marten, Stone, — Size and quality similar to the baum 
marten. The color of the under-hair is stony white, and the 
top-hair is a very dark brown, almost black. Skins of a pale 
bluish tone are used natural, while less clear colored ones are 
dyed, usually in Russian sable shades. They are found in 
Russia, Bosnia, Turkey, Greece, Germany, and France, 
the best coming from Bosnia and France. 

Mink. — 16 X 5 inches. Is of the amphibious class, and 
is found throughout North America, as well as in Russia, 
China and Japan. The under-hair is short, close and even, 
as is also the top-hair, which is very strong. The best skins 
are very dark, and come from Nova Scotia. In the central 
states the color is a good brown, but in the northwest and 
southwest, the fur is coarse and pale. It is very durable and 
an economic substitute for sable. The Russian species is 
dark, but poor and flat in quality, and the Chinese and Japa- 
nese sorts are so pale that they are always dyed. 

14 



FURS AND THEIR CHARACTERISTICS 

Mole. — 3^ X 2^ inches. Is plentiful in the British Isles 
and Europe, and is much in demand on account of its vel- 
vety fur of a pretty bluish shade. Although the skins are 
comparatively cheap, the cost of dressing is high on account 
of the considerable amount of labor involved. The pelt is 
very light in weight, but does not resist well the friction of 
wear. 

Monkey, Black. — 18 X 10 inches. The species usually 
found on the west coast of Africa, is the one of interest to 
the fur trade. The hair is very long, very black and bright, 
with no under-hair, and the white pelt is very noticeable by 
contrast, 

Muskrat, Brown, Black, Russian. — 12 X 8 inches. A 
very prolific rodent of the amphibious class, obtained in 
Canada and the United States. It has a fairly thick and 
even brownish under-hair, and a rather strong, dark top- 
hair of medium density. It is a durable and not too heavy 
fur. It is used natural, but recently the plucked, sheared 
and dyed skins have found a very extensive use as Hudson 
seal, an imitation of real seal. The so-called black variety 
of muskrat is found in New Jersey and Delaware, but only 
in comparatively small numbers. The Russian is also very 
small and limited in numbers. It is of a pretty silvery-blue 
shade with even under-hair, with very little silky top-hair, 
and silvery-white sides, presenting altogether a marked 
effect. 

Nutria. — 20 X 12 inches. Is a rodent about half the size 
of the beaver, and when plucked, has only about half the 
depth of fur, which is not so close. It is often dyed a seal 
color, but its woolly nature renders it less effective than the 
dyed muskrat. The skins are obtained from northern South 
America. 

Opossum, American. — 18 X 10 inches. Is a marsupial, 
the only one of its class found outside of Australia. The 
under-hair is of a very close frizzy nature, and nearly white, 
with long bluish-grey top-hair mixed with some black. It 

15 



FUR DRESSING AND FUR DYEING 

is found in central sections of the United States, and is fre- 
quently dyed imitation skunk. 

Opossum, Australian. — 16 X 8 inches. Is of a totally 
different nature from the American. Although it has fur- 
hair and top-hair, the latter is sparse and fine, so that the 
fur coat may be considered one of close even under-hair. 
The color varies according to the district of origin, from 
blue-grey to yellow with reddish tones. 

Those from near Sidney are a light clear blue, while those 
from Victoria are a dark iron-grey, and stronger in the fur- 
hair. The most pleasing shade of grey comes from Adelaide. 
The reddest are the cheapest. The ring-tailed opossum, 
7x4 inches, has a very short, close and dark grey under-fur, 
some almost black, but the skins are not used extensively. 
The Tasmanian opossum, grey and black, 20 x 10 inches, 
is of a similar description, but larger, darker, and stronger in 
the under-hair. 

Otter, River. — The size varies considerably, as does also 
the length of the fur, according to the origin. It is found 
in greatest numbers in the coldest northern regions, and with 
the best under-hair, the top-hair being unimportant, as it is 
plucked out. Most of the best river otters come from 
Canada and the United States, and average 36 x 18 inches. 
The skins from Germany and China are smaller and shorter 
furred. The colors of the under-hair vary from very dark 
brown to almost yellow. Both the fur and the leather are 
extremely strong, and many skins are dyed imitation seal 
after plucking. 

Otter, Sea. — 50 x 25 inches. Is one of the most beauti- 
ful of furs. The under-hair is of a rich, dense, silky nature, 
with short and soft top-hair, which is not plucked. The 
colors range from a pale grey-brown to a rich black, and 
many skins have a sprinkling of white or silver-white hairs. 
The blacker the under-hair, and the more regular the silver 
points, the more valuable is the skin. 

Pony, Russian. — This is a comparatively cheap, but 

16 



FURS AND THEIR CHARACTERISTICS 

very serviceable fur, and possesses some very desirable 
qualities. It has a thin leather, but is also scantily haired. 
Young pelts have a design on them somewhat similar to 
broadtail lambs, or moire astrachans, but this design is lost 
to a considerable degree by dyeing the furs. The hair, 
which is very glossy, is generally dyed black, although the 
natural pelts are also worn extensively. 

Rabbit. — 10 x 16 inches. The fur is thick and fine, but 
the pelt is very weak. It is a native of central Europe, 
Asia, North and South America, New Zealand and Aus- 
tralia. The color ranges from white to black. France, Bel- 
gium and Australia are the greatest producers of rabbits 
suitable for dyeing biack, the so-called French seal, for 
which they are mostly used. At the present time the dyeing 
of rabbits constitutes a considerable percentage of the total 
fur-dyeing operations in this country. The most varied 
shades are produced on rabbit, and it probably is the basis 
of the greatest number of dyed imitations of better furs. In 
addition to the French seal, or sealine, rabbit is dyed in 
imitation of beaver, mole, etc. 

Raccoon. — 20 x 12 inches. Varies considerably in size, 
quality and color of the fur, according to the part of North 
America in which it is found. The under-hair is l-H inches 
deep, pale brown, with long top-hair of a dark and silvery- 
grey mixture of a grizzly type, the best having a bluish tone, 
and the cheapest a yellowish or reddish-brown. The best 
skins come from the northern part of the United States. 
The skins have a wide use natural, but are also dyed dark 
blue, or imitation skunk, the latter being a very effective and 
attractive substitute, and extensively used. Sometimes the 
skins are plucked, and if the under-hair is good, the effect 
is similar to a beaver. 

Sable, American and Canadian. — 17 x 5 inches. The 
skins are sold in the trade as martens, but since many of the 
skins are of a very dark color, and almost as silky as Russian 
sable, they have come to be known as sable. The prevailing 

17 



FUR DRESSING AND FUR DYEING 

color is a medium brown, while many are quite yellow. 
These pale skins have been dyed so well that they can 
cheaply substitute Russian sable. The finest skins are from 
the Eskimo Bay and Hudson Bay districts, the poorest from 
Alaska. 

Sable, Russian. — 15 x 5 inches. Belongs to a species of 
marten similar to the European and American, but much 
more silky in the texture of the fur. The under-hair is 
close, fine and very soft, the top-hair is regular, fine and 
flowing, and silky, ranging from H to 2^ inches in depth. 
In color they vary from a pale stony or yellowish shade to 
a rich, almost black, dark brown, with a bluish tone. The 
leather is exceedingly close and fine in texture, very light in 
weight, and very durable. The Yakutsk, Okhotsk, and 
Kamchatka sorts are good, the last being the largest and 
fullest-furred, but of less color density than the others. The 
most valuable, are the darkest from Yakutsk in Siberia, par- 
ticularly those having silvery hairs evenly distributed over 
the skin, but these furs are very rare. 

The Amur skins are paler, but often of a pretty, bluish 
tone, with many interspersed silvery hairs. The fur is not 
so close or deep, but is very effective nevertheless. The 
paler skins from all districts are now tipped, the tips of the 
hair being stained dark, the fastest dyes being used, and 
only an expert can detect them as differing from the natural 
shades. 

Seal, Fur. — The sizes range from 24 x 15 inches to 
15 X 25 inches, the width being the widest part of the skin 
after dressing. The most useful skins are the pups 42 inches 
long, the quality being very good and uniform. The largest 
skins, known as wigs, and ranging up to 8 feet in length, 
are uneven and weak in the fur. The supply of the best 
sort is chiefly from the northern Pacific, Pribilof Islands, 
Alaska, northwest coast of America, Aleutian Islands, and 
Japan. Other kinds are taken from the south Pacific re- 
gions. The dressing and dyeing of seal takes longer than for 

18 



FURS AND THEIR CHARACTERISTICS 

any other fur, but when finished, it has a fine, rich effect, 
and is very durable. 

Seal, Hair. — This is chiefly used for its oil and leather, 
and not for its fur. It has coarse, rigid hair, and no under- 
hair. 

Skunk, or " Black Marten." — 15 X 8 inches. The 
under-hair is full, and fairly close, with glossy, flowing top- 
hair about 2^ inches long. The majority of the skins have 
two stripes of white hair extending the whole length of the 
skin. These were formerly cut out, but more recently are 
dyed the same color as the rest of the skin. They are widely 
found in North and South America. The best are from Ohio 
and New York. The skunk is naturally the blackest fur, 
is silky and very durable. 

Squirrel. — 10 X 5 inches. This size refers to the Russian 
and Siberian types, which are practically the only kind im- 
ported for fur, other species having too poor a fur to be of 
great commercial interest. The back of the Russian squirrel 
has an even, close fur, varying from a clear bluish-grey to 
a reddish-brown, the bellies in the former being of a flat 
quality and white, in the latter, yellowish. The backs are 
worked up separately from the bellies. The pelts, though 
light in weight, are tough and durable. The tails are dark 
and very small, and considerably used. 

Tiger. — The size varies, the largest measuring about 10 
feet from the nose to the root of the tail. It is found 
throughout India, Turkestan, China, Mongolia, and the 
East Indies. Coats of the Bengal variety are short and of a 
dark orange-brown with black stripes. Those from other 
parts of India are similar-colored, but longer in hair, while 
those from the north and China are not only large in size, 
but have very long soft hair of a delicate orange-brown, with 
very white flanks, and marked generally, with the blackest 
of stripes. 

Wolf. — 50 X 25 inches. Is closely allied to the dog 
family, and very widely distributed over the world. The 

19 



FUR DRESSING AND FUR DYEING 

best are the full-furred skins of a very pale bluish-grey with 
fine, flowing black top-hair, from the Hudson Bay district. 
Those from the United States and Asia are harsher and 
browner. The Siberian is smaller than the North American, 
and the Russian still smaller. A large number of prairie- 
dogs, or dog-wolves, is also used for cheaper furs. 

Wolverine. — 16 X 18 inches. Is a native of America, 
Siberia, Russia, and Scandinavia, and is of the general na- 
ture of the bear. The under-hair is full and thick, with 
strong, bright top-hair about 2^ inches long. The color is of 
two or three different shades of brown on one skin, the 
center being dark, and presenting the general appearance 
of an oval saddle, bordered with a rather pale shade of 
brown, and merging to a darker shade towards the flanks. 
This peculiar character stamps it as a distinguished fur. 
It is expensive, and quite valuable on account of its excellent 
qualities. 

Wombat, Kaola or Australian Bear. — 20 x 12 inches. 
It has a light grey or brown, close, thick under-hair ^ inch 
deep, and no top-hair, with a rather thick, spongy pelt. It 
is cheap, and well suited for rough wear. 



20 



CHAPTER II 
STRUCTURE OF FUR 

FUR is made up of two main components, the hair 
and the skin, and each of these has a very complex 
structure. 

In the living animal the skin serves as a protective cover- 
ing, and also constitutes an organ of secretion and of feel- 
ing ; consequently it is of a highly complicated nature. The 
skin of all fur-bearing animals is essentially the same in 
structure, although varying considerably as to thickness 
and texture. It consists of two principal layers, which are 
entirely different in structure and purpose, and correspond- 
ingly different in both physical and chemical respects: the 
epidermis, epithelium or cuticle, w^hich is the outer layer, 
and the dermis or corium, which is the true skin. (Fig. lA). 

The epidermis is very thin as compared with the corium. 
Its outer layer consists of a tissue of cells, somewhat analo- 
gous to the horny matter of nails and hair. The inner sur- 
face, called the ' rete malpighi,' rests on the true skin, and 
is a soft, mucous layer of cells. These cells are spherical 
when first formed, but as they approach the surface become 
flattened, and dry up, forming the horny outer layer of the 
epidermis, which is constantly throwing off the dead scales, 
and which is constantly being renewed from below. It is 
from this inner layer of the epidermis that the hair, the 
sweat-glands, and the fat-glands are developed. 

The corium, or true skin, consists essentially of white, 
interlacing fibres of the kind known as connective tissue. 
These fibres are themselves made up of extremely fine 
smaller fibres, or fibrils, cemented together by a substance 
of a somewhat different nature from the fibres, the coriin. 
Towards the center of the skin, the texture of the interweav- 

21 



Fill DUES^lxN'Cl AM) FIR DYELNCi 

iuii- fibres is looser, becoming- imu'h nuno I'lnnpact at the siir- 
faee just beneath the inner layer of the epidermis. This 
part oi the eorium is so exeeediniily close that the fibrils are 
scarcely recoii'ni/.able. It is in this ]iart that the fat-glands 
are situated, while the hair-roots and sweat-glands pass 
through it into the looser texture of the eorium. The sur- 
face next to the tlesh is also closer in structure than the 
middle portions of the skin, and has somewhat of a mem- 
branous character due to the tibres running almost parallel 
to the surface of the skin. The skin is joined to the body 
proper by a network of connective tissue, frequently full 
of fat-cells. This layer, together with portions of the Hesli 
which may adhere to it. is removeil by the process called 
* tleshing.' and this side of the skin is known as the flesli 
side. The eorium also contains a small proportion of yellow 
fibres, known as ' elastic tibres," which ditfer physically and 
chemically from the rest of the skin substance. 

During the course of the development of the embryo ani- 
mal, a small group of cells forms like a bulb on the inner side 
of the epidermis, aboxe a knot of very fine blood-vessels in 
the eorium. This group of cells grows downward into the 
true skin, and the hair-root which is forme^l within it. sur- 
rounds the capillary blood-vessels, drawing nourishment 
from them, and thus forming the papilla. I Fig. 1A\ 
Smaller projections also form on the bulb, and the fat-glands 
are gradually developed. The sweat-glands are formed in 
a manner similar to the development of hair. 

The individual hair tibre is quite as complicated in struc- 
ture as the skin, and is made up of four distinct parts. 
l^Fig. IBV^ 

The medulla, or pith, is the innermost portion of the hair, 
and is composed of many shrunken cells, often connected 
by a network which may fill the medullary colunm partially 
or wholly. 

1 Descriptions ;uid figuros taken from " Mammal Fur Under the Mi- 
croscope." by Dr. L. A. Hausman. in Xotural Hi^torij. Sept.-Oot.. 1920. 



STRUCTURE OF FUR 



Surrounding the merlulla is the cortex, which is made up 
of spindle-shaped cells fused into a horny, almost homo- 
geneous, transparent mass, and forming a large proportion 
of the hair shaft. 

In the majority of the fur-bearing animals, there is dis- 
tributed within and among the cells of the cortex a pigment 
in the form of granules or minute particles, arranged in 
the different hairs in fairly definite and characteristic pat- 
terns. It is to these pigment granules that the color of the 
hair is due primarily. In s(^me cases the coloring matter 
of the shaft is uniformly diffused and not granular. 




A 



A. Structure of Skix. 



Cutfcle 
Cortex 
Medulla 



— Epidermis (ou+er Iqyer) 
Epidermis (inner layer) 

-True skin or Dermis 

Oil gland 

Muscles which move the 

hoir 

Follicle (inner loyer) 

Follicle (oirferlayer) 

Popilla inclosed in Bulb 

- Root sheath (mner layer) 

Root sheath (outer layer) 

Blood and nerve supply 
to the hair 



Medulla. 



Fig. 1 




Jf^ scale 



4/^_^^Piqment 
<' t 1 granules 

' 'i 



B. Structure of Hair. 



The outermost coat of the hair, or cuticle, is composed 
of thin, colorless, transparent scales of varying forms and 
sizes, and arranged in series like the shingles of a roof. It 
is on these scales that the lustre or gloss of the hair depends. 
Since lustre is due to the unbroken reflection of light from 
the surface of the hair, the smoother the surface, the glossier 
it will appear. When the scales of the cuticle are irregular 
and uneven, the surface of the hair will not be uniform and 



23 



FUR DRESSING AND FUR DYEING 

smooth, and the light reflected from it will be broken and 
scattered, and consequently the hair will not possess a high 
degree of lustre. As a rule, the stiff, straight hairs have the 
most regular and uniform arrangement of the scales of the 
cuticle, and hence are the smoothest and glossiest. 

Fur hairs are in general either circular or elliptical in 
cross-section, those which are circular being straight or only 
slightly curved, while those which are elliptical in cross-sec- 
tion are curly like the hair of the various kinds of lambs. 

Most fur-bearing animals have two different kinds of hair 
on their bodies. Nearest to the skin is a coat of short, thick, 
soft and fine hair, usually of a woolly nature, and called the 
under-hair, under-wool, or fur-hair. Overlying the fur-hair 
is a protective layer of hair, longer and coarser than the 
under-hair, and usually straight, hard, smooth and glossy. 
This is called the top-hair, over-hair, guard-hair or protec- 
tive hair. In some furs, the top-hair constitutes one of the 
chief elements of their beauty, while in others, the top- 
hairs are removed, so as better to display the attractive 
features of the, under-hair. The roots of the top-hair are 
generally deeper in the skin than those of the fur-hair, and 
in some instances where the top-hair is removed, as in the 
seal, the roots are destroyed by the action of chemicals 
applied to the skin side, the roots of the fur-hair being 
wholly unaffected by this treatment. 

The fur-hair and the top-hair in the same animal have 
different medullary and cuticular structures, and these 
characteristics may be used to distinguish the two kinds of 
hair. Figs. 2A and B illustrate these differences. In each 
case, the two large hairs on the left of the illustration are 
the guard-hairs, showing respectively the cuticular scales 
and the medulla. On the right are the two fur-hairs showing 
the scales and the medulla. 

Although composed of many different kinds of tissues, 
and varying so greatly in physical structure, both the skin 
and the hair belong to the same class of chemical com- 

24 



STRUCTURE OF FUR 



pounds, namely the proteins. These are highly complex 
substances, forming the basis of all animal and vegetable 
tissues. There are many different kinds of proteins, varying 
somewhat in their constitutions, but all show, on analysis 
the following approximate composition of chemical 
elements : 

Carbon 50-55% 

Hydrogen 6.5-7.3% 

Nitrogea 15-17.6% 

Oxygen 19-24% 

Sulphur 0.3-5% 

The principal kinds of proteins found in the various fur 
structures are albumins, keratin, collagen, and mucines. 
Albumins, of which the white of egg is the most familiar 





A. Hair of European Beaver. 
a. Top-hair. b. Under-hair. 



Fig. 2 



B. Hair of Skvnk. 
a. Top-hair. b. Under-hair. 



variety, occurs to some extent in the corium as serum in the 
blood-vessels, and also as the liquid filling the connective 
tissues, known as the lymph. They are soluble in cold 
water, but when heated to about 70°C., they coagulate and 
are then insoluble. Concentrated mineral acids and strong 
alcohol will also effect coagulation. 

Keratin is the chief substance of which all horny parts of 
the animal body are composed, such as the hair, nails or 
hoofs. It is the principal constituent of the hair, the epi- 
dermis, and the walls of the cells of the inner layer of the 



25 



FUR DRESSING AND FUR DYEING 

epidermis, or the ' rete malpighi.' Keratin is particularly 
rich in sulphur, and is quite insoluble in cold water. Caustic 
alkalies attack keratin-containing parts. 

The collagens are the principal proteins of the skin, form- 
ing largely the substance of the connective tissue fibres, and 
consequently the framework of the skin. They are insoluble 
in cold water, dilute acids and salt solutions, and are only 
very slowly attacked by dilute alkalies. Dilute acids and 
alkalies cause collagen to swell; concentrated acids, vegeta- 
ble tanning materials, basic chrome or iron salts cause it 
to shrink. By boiling with water, dilute acids or dilute 
alkalies, collagen is split up into gelatin or glutin. 

The mucines of the skin, intercellular material or coriin, 
are soluble in dilute acids, in dilute solutions of alkalies and 
of alkaline earths such as lime, and in 10% salt solution, 
but insoluble in water, and in salt solutions of greater or less 
concentration than 10%. On drying the skin, the mucines 
cement the connective tissue fibres, causing the skin to be- 
come stiff, horny and translucent. The mucines are also 
constituents of the cells of the ' rete malpighi.' The solu- 
bility of the mucines in dilute solutions of alkalies and of 
alkaline earths causes the epidermis to be loosened from the 
corium, when the skins are treated with such solutions for 
some time. 

When raw skins are boiled with water, the greater part 
goes into solution, the residue consisting chiefly of the kera- 
tins of the hair and epidermis cells. On cooling, the solu- 
tion solidifies to a jelly of gelatine. It combines with both 
acids and alkalies. A property of the skin which is of im- 
portance in the tanning operation of fur-dressing, and a 
quality which also characterizes gelatine, is the capacity to 
absorb liquids and swell up, without changing chemically. 
Raw pelts swell up easily in pure cold water, but much more 
easily in solutions of dilute acids or dilute alkalies, only a 
little of the skin material being dissolved. In stronger solu- 
tions, the skins swell up less, while more of the skin sub- 

26 



STRUCTURE OF FUR 



stance dissolves, and by prolonged action of strong acids 
or alkalies, an almost complete solution of the skin is ob- 
tained, without, however, any of the material decomposing. 
With very strong alkalies or acids, the skin substance is 
broken up into simpler compounds, such as various amines 
and ammonia. The swelling action of acids or of alkalies in- 
creases with the increase in concentration of the acid or 
alkali, but only up to a certain point, after which further 
increase in the strength of the acid or alkaline solution 
causes a reduction in the swelling, and even produces 
shrinkage. In the presence of neutral salts, like common 
table salt, sodium chloride, the swelling action of acids, is 
reduced, but the action of alkalies remains practically 
unaffected. 

When treated with the various chemicals, fur hair acts in 
a manner quite similar to wool. If it be remembered that 
certain classes of furs are derived from animals of the 
sheep family, such furs as Persian lamb, krimmer, etc., it 
becomes apparent why chemicals should affect furs in nearly 
the same way as wool. The great majority of furs differ 
from those of the sheep family, in possessing much greater 
resistance to the action of chemicals. The range is a 
wide one however, and no exact criterion can be adopted. 
As a general rule, the reactions are most marked with fur- 
hair of a woolly nature, so this may be taken as a standard 
of reference. 

Acids have relatively little action on the hair, when 
applied in dilute solutions. The scales of the cuticle or epi- 
thelium are somewhat opened, the fibre becoming slightly 
roughened thereby. Even at high temperatures, the hair is 
quite resistant to the action of dilute acids. Concentrated 
acids destroy the hair with the liberation or formation of 
ammonia, hydrogen sulphide, and various amino acids. 
When treated with dilute acids, the hair, especially if it is 
of a very woolly nature, retains considerable quantities of 
acid, this phenomenon being probably due to the fixation 



27 



FUR DRESSING AND FUR DYEING 

of the acid by the basic groups in the hair. Nitric acid 
produces a yellow coloration when applied in dilute solution 
for a short time. Sulphurous acid, the acid formed by the 
burning of sulphur, has a bleaching action on the hair. 

Alkalies attack the hair, even in dilute solutions, and by 
longer action complete decomposition sets in, with forma- 
tion of ammonia and amino-acids. Ammonium carbonate, 
soap, and borax are practically harmless in their effect on 
the hair. Sodium and potassium carbonates roughen the 
hair on prolonged action, even in dilute solutions. Cal- 
cium hydroxide on continued action removes sulphur from 
the hair, causing it to become brittle. 

Salts of alkalies and alkaline earths do not affect the hair 
at all. Salts of the heavy metals on the other hand, are ab- 
sorbed in appreciable quantities. From a dilute solution of 
alum, aluminum hydroxide is absorbed by the hair, the 
potassium sulphate remaining in solution. Similarly with 
copper, iron, and chromium salts, the metal oxides are fixed 
by the fibre. 



28 



CHAPTER III 
FUR DRESSING 

Introductory and Historical 

FUR DRESSING has a twofold purpose. First of 
all, the putrefactive processes must be permanently 
stopped, so that the skin may be preserved as such, 
or worked up as some fur garment, without danger of de- 
composition. Having taken measures to assure the en- 
durance or relative permanency of the pelt, the prime con- 
sideration is, of course, the appearance of the hair. The 
hair must be so treated that all its inherent beauty is 
brought out to the fullest extent. It must be made clean 
and soft, and all the natural gloss must be preserved, and if 
possible, enhanced. The appearance of the leather is rela- 
tively unimportant, since it is not seen after the furs are 
made into garments. There are, however, certain qualities 
which it is essential for the leather to possess after being 
dressed, and these are, softness, lightness of weight, elasticity 
or stretch, and a certain firmness or ' feel.' In other words 
the important considerations in fur dressing are the employ- 
ment of means, and the exercise of care to preserve or even 
improve those characteristics of the pelt which make it 
valuable. 

The dressing of furs has many features in common with 
the manufacture of leather, which is a kindred art. But 
whereas in fur dressing the prime consideration is the ap- 
pearance of the hair, and the leather is of secondary im- 
portance, in the production of leather, the hair plays no part 
at all, since it is entirely removed from the pelt. The fun- 
damental points of resemblance between leather manu- 

29 



FUR DRESSING AND FUR DYEING 

facture and fur dressing are in those processes and operations 
which are concerned with the preservation of the leather, 
and rendering it in the proper condition for use. 

Both leather dressing and fur dressing have an origin 
which may be regarded as identical, and which dates back to 
the haziest periods of antiquity. In the course of satisfying 
his needs, primitive man killed the animals about him, and 
thus obtained his food. The killed animal also furnished 
a skin, which after undergoing certain manipulations and 
other treatments, could serve as a protective covering, orna- 
ment, or defensive weapon. Since the skin in its natural 
state was hardly fit for use because of its easy tendency to 
putrefaction, it is evident that man had to find some means 
of preventing this decay in a more or less permanent fashion, 
and moreover had to treat the skin so that it would be suit- 
able for use, by rendering it soft and flexible. The discovery 
of means to accomplish these purposes was probably one of 
the first great steps forward on the path of progress and 
civilization. 

There are evidences of the use of animal skins in the 
earliest periods of antiquity, in fact it is a usage which may 
be literally regarded as '' old as the hills." One of the 
earliest written records of the employment of the skins of 
animals as garments, is in the Old Testament, where it 
states, '' Unto Adam and to his wife did the Lord God make 
coats of skins, and clothed them." Numerous other biblical 
references indicate the use of animal skins for various pur- 
poses, sometimes prepared as leather, with the hair removed. 
Among the Egyptians tanning seems to have been a com- 
mon occupation. The particularly attractive skins, like 
those of the leopard or panther, were especially prized, 
and were made up as furs for ornamental wear, rugs and 
decorations. The less valuable skins were unhaired and 
made into leather. Although the tanning or leather-pro- 
ducing processes of the Egyptians are quite unknown, 
numerous figures engraved in stone afford an indication to 

30 



FUR DRESSING — INTRODUCTORY 

some of the manipulatory operations, such as soaking the 
skins, fleshing, softening with stones, stretching over a 
three-legged wooden " horse," etc. Many articles, made of 
leather, have been found in the various Egyptian sar- 
cophagi, and all are in a splendid state of preservation, 
after forty centuries, thereby indicating a very efficient 
method of dressing animal skins. Likewise, the presence 
in the museums of various articles, leather and fur, of As- 
syrian, Phoenician and Persian origin, tends to show that 
these peoples also possessed a considerable degree of profi- 
ciency in tanning. Frequent references in the Greek litera- 
ture show that leopard and lion skins were worn as war 
cloaks, and they undoubtedly were properly made. In the 
Iliad is described an operation for the preparation of skins 
for use as garments, and the method seems to be a sort of 
chamois dressing. 

The first method of tanning skins was, in all probability, 
that of rubbing into the skins various fatty materials found 
close at hand, such as parts of the animal, fat, brains, milk, 
excrement, etc., such an operation constituting the basis of 
what is now known as the chamois dressing. One of the 
reasons for believing that it was the first process to be used 
by primitive man, is the fact that certain undeveloped tribes 
and races of the present day still dress skins by it. The 
American Indians, even to this day prepare skins by rubbing 
in, on the flesh side, the brains of the animals which furnished 
the skins. The Eskimos dress skins by rubbing in animal 
fats or flsh-oil, and subsequently softening and stretching 
the skins with their teeth in place of, or for want of other 
implements. Usually, however, variously shaped stones 
or bones of animals are used to obtain the proper degree of 
softness and flexibility. It is true, too, that some of the 
skins dressed in this primitive fashion can scarcely be ex- 
celled by any dressed with more modern processes and tan- 
ning methods. 

The next step forward in the preparation of animal skins 

31 



FUR DRESSING AND FUR DYEING 



for use was undoubtedly the utilization of substances found 
in the earth. Common salt, sodium chloride, was the most 
universally used substance of mineral origin, just as it is 
today. Our prehistoric ancestors eventually discovered the 
preservative action of salt, and applied it to skins. While it 
was effective, it was not sufficiently permanent, so another 
mineral, also of very common and wide occurrence was used 
in combination with the salt, and the result proved quite 
satisfactory. This second common mineral was alum. The 
use of alum, which is the basis of numerous tanning pro- 
cesses to this day, seems to have been quite a popular method 
of ancient times. Artemidorus, a Greco-Roman writer, 
mentions the use of alum by the Greeks, and the Romans 
are known to have prepared a soft, flexible leather called 
aluta (alum leather), by using it. In view of the fact that 
Egypt had extensive deposits of alum, it is believed that the 
alum-salt process was employed also by the Egyptians in 
the preparation of leather. However, the evidence on this 
point is not conclusive. 

One of the most important methods of producing leather, 
either as such or on furs, was with the aid of certain vegeta- 
ble extracts, known as the tannins, from which the process 
of tanning gets its name. The discovery of the value of 
these materials for converting the decaying raw skin into 
a leather which could be preserved for an almost indefinite 
length of time, and which was flexible and soft as desired, 
was of far-reaching importance. For it is only in very recent 
times that these tannins have been superseded in part by 
new tanning substances whose use is simpler and more 
time-saving. Yet there are unmistakable indications that 
the tannins were employed for tanning at a period which 
reaches back to the dawn of history. Although it is scarcely 
probable that the people who used these materials could 
have known of the existence or the nature of the particular 
substances in the vegetable extracts which actually effect 
the tanning action, experience taught them to employ these 

32 



FUR DRESSING — INTRODUCTORY 

plants which possessed the highest content of active ingredi- 
ents, and which, consequently, were most effective in use. 
Tychios, of Boetius, a Greek supposed to have lived about 
900 B.C. and mentioned in the Iliad, is considered the oldest 
known tanner, and was regarded by Pliny, a Roman writer, 
as the discoverer of tanning, and of the use of the various 
vegetable tanning materials. At any rate, the Greeks used 
the leaves of a so-called tanning-tree, which was probably 
the sumach. The Egyptians worked with the acacia, while 
the Romans used as tanning materials the barks of the pine, 
alder and pomegranate trees, also nut-galls, sumach and 
acorns. The Romans were quick to employ methods used by 
the peoples whom they conquered, and it is in this way that 
they learned the use of many of the plants mentioned, for 
tanning purposes. 

Many other ancient peoples had various processes of tan- 
ning, the methods probably differing in each country. Thus 
the Chinese, Syrians, and much later, the IMoors, were each 
known for proficiency in a certain class of leather tanning. 
It has been said that in general, even up to modern times, 
tanning with nut-galls was the characteristic method of the 
Orient; with oak-tan, that of the Occident, while the use of 
alum is regarded as the method peculiar to the Saracens. 

In prehistoric times and the early centuries of civilization, 
skins or pelts were prepared for use by the individual, the 
work usually being done by the housewife and daughters, 
while the masculine members of the family were engaged in 
hunting the animals and obtaining the skins. At a later 
period, when people had advanced to the point where they 
lived in cities, the preparing or dressing of skins became cen- 
tered in the hands of a comparatively small number of 
people, and thus the work took on the aspects of a trade. 
The workers in fur were at first the same people who made 
leather out of the skin, for the two kinds of work were very 
closely associated. During the period of the Roman su- 
premacy, historical records show that the furriers, who did 

33 



FUR DRESSING AND FUR DYEING 

all the work connected with furs, from purchasing the raw 
skins, dressing them, making them into garments, to selling 
the latter, were organized into associations together with 
the leather workers. After the fall of the Roman empire, 
and throughout the centuries known as the Dark Ages, all 
traces of the furriers seem to have been lost, but in the be- 
ginning of the Renaissance period in the fourteenth and 
fifteenth centuries, we again find records of the furriers, who 
were now all members of the furriers' guilds, also in associa- 
tion with the leather workers. As formerly, all the work 
connected with the production of fur apparel from the raw 
furs, was done by the master furrier and his apprentices. 
The methods and the implements used, were essentially the 
same as in Roman times, and in fact, up to a very recent 
period there was very little change in either. 

With the advent of the great industrial era at the begin- 
ning of the nineteenth century, the guild system became 
ineffective, but the furriers continued their work as here- 
tofore. Up to about the middle of the nineteenth century, 
the furrier continued to be the only factor of any importance 
in the fur trade. There was no need for speed in his work, 
for the demands of the trade were not so urgent. The fact 
that the dressing of furs often occupied two to four weeks 
was no deterring factor in his business. However, with the 
great expansion of the fur trade about this time, it became 
impossible for the individual furrier to do everything him- 
self, and keep up with the requirements of his customers. 
Specialization commenced, and establishments were set up 
solely for fur dressing. The traditional time- and labor- 
consuming processes were still used, but the efficiency of 
work on a large scale enabled the fur dressers successfully 
to fill their orders. But the fur trade continued to grow 
by leaps and bounds, and very soon the fur dressers were no 
longer able to meet the demands of the trade. It was then 
that the science of chemistry came to the aid of the fur 
dresser, and helped him meet the exigency. By devising 

34 



FUR DRESSING — INTRODUCTORY 

dressing processes which were cheap and efl&cient, and which 
only required several hours, or at the most one or two days, 
as compared with as many weeks, the chemist brought the 
fur dresser out of his dilemma. And with the adoption of 
mechanical time- and labor-saving devices, the fur dressing 
industry has made wonderful progress. 



35 



CHAPTER IV 
FUR DRESSING 

Preliminary Operations 

THE fur dresser receives the skins in one of two 
shapes, flat or cased, depending on the manner in 
which they were removed from the animal. Flat 
skins, as for example, beaver, are obtained by cutting on the 
under side of the animal from the root of the tail to the 
chin, and along the inner side of the legs from the foot to 
the first cut. The skins are either fastened to boards or at- 
tached to wooden hoops slightly larger than the skins, so 
as to stretch them, and are then carefully dried, avoiding 
direct sunshine or artificial heat, as it is very easy to over- 
heat the skins and thereby ruin them. The great majority 
of skins, however, are cased. The pelts are cut on the 
under side of the tail, and along the hind legs across the 
body, the skin being then removed by pulling it over the 
head off the body like a glove, trimming carefully about the 
ears and nose. The skin is thus obtained inside out. and 
is drawn over a stretching board or wire stretcher of suitable 
shape and dimensions, so as to allow the skin to dry with- 
out wrinkling. The pelts, after drying in a dry, airy place, 
are removed from the stretchers and. are ready for the mar- 
ket. With some furs, as foxes, the skins are turned hair-side 
out while still somewhat moist, and then put on the stretcher 
again till fully dried. In most cases, however, skins are sold 
flesh-side out. Throughout the various dressing' opera- 
tions cased skins are kept intact, being turned flesh-side out 
or hair-side out according as the processes are directed to 
the respective sides. The pelts are only cut open if they 

36 



PRELIMINARY OPERATIONS 



have to be dyed, or after the manufacturer receives them, 
when they have to be worked into manufactured garments. 

A distinction which is made by fur dressers and dyers, and 
also by the fur trade in general, divides furs into those de- 
rived from domestic animals, particularly the various kinds 
of sheep, including also the goat species, and those obtained 
from other animals by trapping. In fact, at one time, and 
to a certain extent even to-day, dressers were divided into 
two groups based on this distinction, one class dealing only 
with furs obtained from the sheep family, and the other 
working with other kinds of furs. This differentiation is not 
a simple arbitrary one, but has a rational justification. As 
mentioned before, the manner and habit of living of the ani- 
mal are important factors in determining the nature and 
constitution of its skin, both leather and hair. The structure 
of the body being dependent primarily upon the nature of 
the food absorbed by the animal, it is only natural that 
herbivorous or vegetable-eating animals such as sheep and 
goats, should possess fur of a different sort from that of the 
carnivorous or meat-eating animals, such as the majority 
of fur-bearers are. It also seems clear that furs differing in 
their character and constitution should require somewhat 
different treatments, and accordingly the methods are modi- 
fied when furs like lambs or goats are dressed. To a great 
extent, however, the fundamental operations are similar for 
all furs, regardless of nature or origin, and these will be 
discussed briefly. 

Inasmuch as the first great purpose of fur dressing is to 
render the skins more or less permanently immune from the 
processes of decay, it is necessary to prepare the pelts so 
as to be most fit to receive the preserving treatment. The 
skins as they are delivered to the fur dresser have, in the 
majority of cases, been stretched and dried to preserve them 
temporarily, while in some instances, especially with the 
l^ger furs like bears and seals, they are salted and kept 
moist. The flesh-side of the pelt still has considerable fleshy 



37 



FUR DRESSING AND FUR DYEING 



and fatty tissues adhering to it, and the hair is generally- 
soiled and occasionally blood-stained. In order to get the 
pelts into such a condition that they can be worked and 
manipulated, they first have to be made soft and flexible. 
Very greasy skins are scraped raw in 
order to remove as much as possible 
of the attached fat, the operation being 
known as beaming or scraping. The 
typical beam, shown in Fig. 3, consists 
of a sloping table usually made of some 
hard wood, and placed at an angle of 
about 45°. It is generally flat, al- 
though in some instances convex beams 
are also used, about a yard long, 8 to 10 inches wide, and 
firmly supported at the upper end. The skin is placed on 
the beam, flesh-side up, and is scraped with a two-handled 
knife (Fig. 4), always in a downward direction. 




Fig. 3. Beam. 




3eaming Knife, or Scraper 




Shaving Knife. 

Fig. 4. Knives Used in Fur Dressing. 



The first step in softening the skins is to get them thor- 
oughly moistened, and this is variously done, depending 
on the nature of the skin. Lambs, for example, require the 
gentlest means of wetting them, while rabbits can stand 



38 



PRELIMINARY OPERATIONS 



soaking in water for several days. The manner and duration 
of moistening must be adjusted to the character of the pelt. 
For the putrefactive processes which were stopped by- 
stretching and drying the skins, continue as soon as the 
pelt is again moistened. The progress of decay causes the 
evolution of certain gases, the simplest of which is am- 
monia, and eventually, if permitted to proceed, brings about 
the complete disintegration of the skin tissue. It has been 
found that a certain amount of gas formation is necessary to 
loosen up the fibres in order to get the best quality of leather 
after tanning. This process must be interrupted at the 
proper time and not allowed to proceed too far. 

Skins which have been preserved fresh by salting, require 
only a comparatively short time (about 2 hours) to become 
softened by soaking in clean, soft water. Most dried skins 
need a longer treatment before they are sufficiently flexible. 
The addition of certain substances to the water facilitates 
and accelerates the softening. In some instances salt water 
is used for soaking the pelts, the preservative action of the 
salt tending to prevent any loosening of the hair. A solu- 
tion of :|% borax is very effective in rendering the skins soft, 
and clean as well. Borax has an exceedingly mild alkaline 
action, and causes a slight swelling of the skin tissue, which 
then absorbs the water more readily. Being also preserva- 
tive and antiseptic, borax tends to prevent decomposition of 
the skin tissue. Another chemical of a different nature, 
but equally effective is formic acid, used in the proportion 
of 1.5-2.5 parts per 1000 parts of water. Formic acid also 
induces a swelling of the skin, the pelts being soaked in a 
short time, and the antiseptic action of the acid obviates 
the possibility of the hair becoming loose. The water used 
should be fresh and clean, and the soaking must be stopped 
as soon as the skins have become soft and flexible. Some- 
times the skins are allowed to soak overnight in water, while 
in other cases, the pelts are just moistened by dipping in 
water until thoroughly wet, and then laying them in a pile 



39 



FUR DRESSING AND FUR DYEING 



for several hours, or overnight. Another method which is 
practised with certain types of skins is the use of wet saw- 
dust or of sawdust moistened with salt water. The fur skins 
are either embedded in the sawdust or drummed with it 
for several hours, or until sufficient moisture has been ab- 
sorbed to render them flexible. By this means there is no 
danger of the skins being over-soaked, or of the hair being 
loosened. When the skins have been properly wetted, they 
are drawn with the flesh-side across the edge of a dull 
knife-blade, in order to help loosen the texture of the skin. 
They are then put into a tramping machine and worked 
until completely softened. In the case of large or heavy 
skms, the moistened pelts are worked on the beam with a 
dull beaming knife to impart thorough softness and 
flexibility. 

The .pelts are then cleaned with particular reference to 
the hair. With some furs this is accomplished simply by 
drumming for several hours with dry sawdust, whereby the 
oil and dirt' are removed from the hair, and the hair is then 
freed from the sawdust by caging. Other skins are washed, 
being passed through a weak soap solution for a short time, 
the dirty spots being brushed. Occasionally an extract of 
soap-bark is used in place of the soap, being even more effec- 
tive. The cleansed skins are then thoroughly rinsed to re- 
move any of the cleaning material, which would affect the 
gloss of the hair if allowed to remain on the skins. Then in 
order to eliminate as much as possible of the water in the 
skins, they are hydro-extracted, a centrifugal machine of 
the type shown in Fig. 5 being used. The basis of its action 
depends on the utilization of the principle of centrifugal 
force. The machine consists essentially of a perforated 
metal basket generally made of copper, capable of being 
rotated at a high speed. Surrounding the basket is an iron 
framework, polished or enamelled on the inside. The wet 
skins are placed in the rotating basket, fur side toward the 
perforations, and the water which is thrown off from the 

40 



PRELIMINARY OPERATIONS 



skins passes through the little holes, and is caught up on the 
walls of the outside frame, from where it is led off through 
suitable ducts. The centrifugal device is properly equipped 
with balancing and regulating attachments, as well as with 
a brake. The power may be applied by the over-drive or 
the under-drive as is most desirable in the particular case. 




Fig. 5. Centrifugal Machine. 
{Fletcher Works, Inc., Philadelphia) 

The inner surface of the basket can also be enamelled or 
otherwise made resistant to the action of acids or other 
chemicals. 

When the skin is removed from the animal, as much as 
possible of the adhering fat and flesh is scraped off, but in 
spite of this, and in spite of subsequent beaming by the 
fur dresser, there is always a thin layer of flesh and fatty 
material remaining and this must be removed so as to ex- 
pose the corium, enabling the efficient action of the chemi- 
cals used in the tanning processes. The process of removing 
this undesirable layer from the flesh-side is known as flesh- 
ing. It is a rather delicate operation, requiring considerable 
experience and dexterity on the part of the worker, for it is 
exceedingly easy to cut into the skin and damage the fur. 

41 



FUR DRESSING AND FUR DYEING 

A fleshing knife of the type commonly used is shown in 
Fig. 6. It consists of a sharp blade fastened at a slight angle 
from the vertical, with the cutting edge away from the 
workman, who straddles the bench, and by drawing the 
skins back and forth across the edge of the blade, removes 
all flesh and fat, leaving the corium free and clean. Large 
skins cannot conveniently be fleshed in this fashion. They 




Fig. 6. Fleshing Knife on Bench. 



are placed on the beam, and fleshed with a fleshing or skiv- 
ing knife similar to the beaming knife, but consisting of a 
slightly curved, sharp two-edged blade having handles at 
both ends. Frequent attempts have been made to use suit- 
able machines to do this work. A type of machine which has 
met with considerable success is depicted in Fig. 7. It is 
fashioned after the models used for the fleshing of hides for 
leather manufacture, and has special adjustments and regu- 
lating devices which afford protection for the hair part of 
the fur. From time to time other fleshing machines are put 
on the market, yet none of them seems to enjoy any great 
popularity, for fleshing is still largely a manual operation. 
With some classes of pelts, fleshing presents some difii- 

42 



PRELIMINARY OPERATIONS 



culties, and chemical means have to be resorted to in order 
to loosen the flesh sufficiently to enable proper fleshing. In 
the case of large furs like bears, leopards, and the like, which 
while of no great importance in the fur trade, are occasion- 
ally met by the fur dresser, the skins after being soaked. 




Fig. 7. Fleshing Machine. 
{Turner Tanning Machinery Co., Peahody, Mass.) 

and washed with soap-water, are partially dried; then the 
flesh-side is treated with technical butter or oil, which is 
tramped in. A mixture of salt water and bran is then ap- 
plied to the skins, thereby causing a swelling action to set 

43 



FUR DRESSING AND FUR DYEING 

in, and the flesh becomes loosened, and is easily removed by 
fleshing on the beam. Seals receive a special treatment 
which makes them soft, and gives them greater stretch 
after they are tanned. A paste made by mixing a very dilute 
solution of caustic soda with an inert substance like French 
chalk, china clay, etc., is applied to the corium after the 
skins have been fleshed, then the pelts are folded up, and 
allowed to lie for several hours. They are then entered 
into a dilute solution of calcium chloride and left overnight. 
After being washed in a paddle or drum, first with fresh 
water, and then in water containing lactic or formic acid to 
remove the lime, the skins are ready for tanning. 



44 



CHAPTER V 
FUR DRESSING 

Tanning Methods 

AFTER the pelts have gone through the preliminary 
operations of softening, washing and fleshing, they 
• are ready to receive the treatment which will con- 
vert the easily decomposing skin into leather of more or less 
permanency, depending on the method used. 

During the past century, considerable study has been 
made both by scientific and technical people, of the prob- 
lem of leather formation. Numerous theories as to the na- 
ture of the process have been evolved, but even to this day, 
no satisfactory explanation has been given which would 
account for all the facts as they are now known, so the 
matter is still a subject of considerable controversy. Proc- 
ter, who is one of the leading authorities on leather today 
discusses the development of the tanning theories as 
follows : 

" The cause of the horny nature of dried skin is that the 
gelatinous and swollen fibres of which it is composed not 
merely stiffen on drying but adhere to a homogeneous mass, 
as is evidenced by its translucence. If in some way we can 
prevent the adhesion of the fibres while drying we shall 
have made a step in the desired direction, and this will be 
the more effective the more perfectly we have split the fibre- 
bundles into their constituent fine fibrils, and removed the 
substance which cements them. The separation of the 
fibres can be partially attained by purely mechanical means, 

45 



FUR DRESSING AND FUR DYEING 

. . . Knapp, to whom we owe our first intelligible theories 
of the tanning process, showed that by physical means the 
separation and drying of the fibres could be so far 
effected as to produce without any tanning agent a sub- 
stance with all the outward characteristics of leather, 
although on soaking it returned completely to the raw 
hide state. He soaked the prepared pelt in absolute 
alcohol, which penetrated between, and separated the 
fibres and at the same time dried them by its strong affinity 
for water. More recently, Meunier has obtained a similar 
result by the use of a concentrated solution of potassium 
carbonate which is even more strongly dehydrating. 

" Knapp made a further step by adding to his alcohol a 
small quantity of stearic acid which, as the alcohol evapo- 
rated, left a thin fatty covering on the fibres which com- 
pletely prevented their adhesion, and reduced their tendency 
to absorb water ; and he so produced a very soft and white 
leather. Somewhat similar are the principles of the many 
primitive methods which apply fatty and albuminous mat- 
ters, grease, butter, milk, or brains to the wet skin, and by 
mechanical kneading and stretching, aided by capillarity, 
work these matters in between the fibres as the water evapo- 
rates. Such methods are still used, and enter into many 
processes in which other tanning agents are also employed. 

" Building upon these facts, Prof. Knapp advanced the 
theory that the effect of all tanning processes was not to 
cause a change in the fibres themselves, chemical or other- 
wise, but merely to isolate and coat them with water-re- 
sisting materials which prevented their subsequent swelling 
and adhesion. True as this theory undoubtedly is in many 
cases, it can hardly be accepted as the whole truth, and it 
seems incontestable that frequently the fibres themselves 
undergo actual chemical changes which render them in- 
soluble and nonadhesive. 

" Before Knapp's work, the prevalent theory, at least as 
regards vegetable tannage, had been a chemical one, started 

46 



TANNING METHODS 



by Sir Humphrey Davy. If a solution of gelatine be mixed 
in proper proportion with one of tannin, both unite to form 
a voluminous curdy precipitate; and, according to Davy's 
ideas, this was amorphous leather. Against this, it was 
urged that even the supposed ' tannate of gelatine ' itself 
could not be a true chemical compound, since the propor- 
tions of its constituents were considerably varied by changes 
in the strength of the solutions, or by washing the precipi- 
tate with hot water; and further, that in chemical com- 
pounds, the form was changed, and no trace of the original 
constituents appeared in the compound; while in leather 
apart from some change of color and properties, the original 
fibrous structure remained unaltered. 

" This reasoning appears much less conclusive now than 
it did in Knapp's day. Against the last objection guncot- 
ton may be quoted as an instance of profound chemical 
change with no alteration in outside appearance; and it 
is recognized that, especially among complex organic sub- 
stances, chemical reactions are rarely complete, but that 
stable positions are reached, so-called ' equilibria,' in which 
the proportion of changed and unchanged substance is de- 
pendent on concentration or other conditions; and that 
therefore such a precipitate might well be a mixture of gela- 
tine with a true gelatine tannate from which further por- 
tions of tannin might be dissociated by water. 

" With the clearing up of old difficulties, however, the 
conflict between chemical and physical theories has, as 
is usually the case, merely passed into a new phase. Years 
ago, it was shown by Linder and Picton and others, that 
liquids could be obtained which were not really solutions of 
ions or molecules, but merely suspensions like that of clay 
in water, or butter-fat in milk; but so finely divided as to 
appear clear and transparent, and pass through filters like 
true solutions. Later, by means of the ultra-microscope 
their discrete particles have actually been made visible, each 
of them consisting of many molecules of the suspended 



47 



FUR DRESSING AND FUR DYEING 

substance. Nevertheless, these particles have many mo- 
lecular properties, possessing plus or minus electrical 
charges; behaving like large ions under the influence of an 
electrical current; and mutually precipitating and neutraliz- 
ing each other when positive and negative are brought to- 
gether. Such solutions are called ' colloid,' and those of 
gelatine and tannin are of the class, so that it is now often 
said that the precipitation of gelatine by tannin, and the 
fixation of tannin by gelatinous fibre are merely ' colloidal ' 
and ' physical,' and not ' chemical ' phenomena. Admitting 
the facts, the question still arises whether the distinction 
between chemical and physical is not here one without a 
difference; and whether between the purely ionized dilute 
solution of a salt and the coarsely granular clay suspension 
there is any point where a definite line of demarcation can 
be drawn. The writer inclines to the view that there is 
not; and that ionic and colloidal combinations are extreme 
cases of the same laws, both physical, and both chemical." 
There are several methods which are used in tanning 
furs, each having its peculiar characteristics and qualities, 
and possessing individual advantages and disadvantages. 
In order to be able to judge the merits of the various proc- 
esses, it is necessary to have a criterion which can serve 
as a basis of reference. Fahrion, a recognized authority 
and investigator in this field, gives a definition of leather 
which is usually accepted as a standard for comparison. He 
says: ''Leather is animal skin, which on soaking in water 
and subsequent drying does not become hard and tinny, but 
remains soft and flexible ; which does not decay in the pres- 
ence of cold water ; and which does not yield any gelatine on 
boiling with water." While the requirements set forth in 
this statement are essential for leather, and a compliance 
with them would also be desirable for tanned furs, a some- 
what less rigorous standard of conditions to fulfil is satis- 
factory for the general needs and purposes of furs. The 
chief qualities which tanned furs must possess, with par- 

48 



TANNING METHODS 



ticular reference to the leather side of the pelt, are reten- 
tion of softness and flexibility after being moistened by the 
furrier for manufacturing purposes, and subsequent drying ; 
and freedom from a tendency to decay during this opera- 
tion and thereafter. If the furs are to be dyed, the effect 
of the dyeing must also be considered, and the tanning must 
be such as to enable the dyed furs to possess the above 
qualities. 

The most important tanning processes employed for furs 
are the following: 

1. Salt-acid tan, or pickle. 

2. Mineral tans. 

3. Chamois tan. 

4. Formaldehyde and similar tans. 

5. Combination tans. 

6. Vegetable tan. 

1. Salt-acid Tan, or Pickle 

This is one of the most extensively used methods for tan- 
ning furs, and is also very cheap and easily applied. A 
typical formula for this tan is the following: A solution of 
salt is prepared containing about 10% of common salt, 
sodium chloride, and to this is added ^-^ ounce of 
sulphuric acid for each gallon of tanning liquor. The 
proportions may be varied within certain limits, but 
the figures here given are those which have proven 
successful in practise. The solution should be made 
in a wooden or earthenware container, free from any 
metal, as it would be attacked by the acid. The liquor 
is then applied to the flesh-side of the fleshed skins 
by means of a brush, making sure to touch all parts 
of the pelt. They are then placed in a pile and allowed to 
rejnain thus until tanned, an operation which occupies a 
time ranging from a few hours to two or three days de- 
pending on the thickness of the skins. When the corium 

49 



FUR DRESSING AND FUR DYEING 

has lost its translucence and has become of a milky-white 
color throughout the entire thickness of the skin, as can 
be seen by viewing a cross-section, the skin may be con- 
sidered tanned. In some instances, where the hair of the 
fur can stand immersion without injury, the skins are 
entered into the pickling solution and allowed to remain 
for 12 to 24 hours, which is generally a sufficient time to 
tan them in this manner. 

The acid of the pickle causes the skin to swell, the salt 
then penetrating between the fibres of the corium, and at 
the same time reducing the swelling of the skin. The acid 
also neutralizes the alkaline products of decomposition 
which may form, while the salt acts as a deterrent to the 
progress of the putrefactive processes. When the skin is 
dried after tanning, and stretched and finished, a soft white 
leather is obtained which is permanent as long as it is kept 
dry. It is the salt which causes the fibres of the skin to be 
completely differentiated and thus prevents their adhesion. 

It is interesting to note that other acids besides sulphuric 
can be used for the pickle, organic as well as mineral, 
formic acid in 1% solution being especially effective and 
giving excellent results, but is more expensive than the 
mineral acid. A method, which in principle is identical 
with the pickle, but carried out in an entirely different 
manner, is the lactic acid fermentation process, or " Schrot- 
beize " as it is called in German. The procedure is in 
general as follows: '' The fleshed skins are placed on tables, 
flesh-side up, and covered with a layer of bruised barley 
grains, or a mixture of 3 parts of wheat bran and 2 parts of 
rye flour. Then the head, tail and legs are turned inward, 
and the skins rolled up in little cushions, hair-side out, and 
placed in a vat. When this is filled with the skins a solu- 
tion of common salt is poured over them, and they are 
allowed to remain thus in a moderately cool place for 24 
hours. After this time, the skins are carefully unrolled, so 
as not to remove any of the adhering solid materials, and 

50 



TANNING METHODS 



turning the skins hair-side inward, they are laid flat to- 
gether in pairs and placed in an empty vat. After another 
24 hours they are again unpacked and replaced in another 
vat, care being taken each time to keep all the solid par- 
ticles adhering to the flesh-side. This operation is con- 
tinued and repeated until the skins are properly tanned, 
which takes from 10 to 14 days, depending on the weather 
and the temperature. The skins are then removed, rinsed 
free of the tanning substances, pressed, dried and finished." 
A somewhat modified form of this process is the so-called 
Russian tan, which is usually done in the following man- 
ner: 5 parts of bruised barley grains are mixed with ten 
parts of luke-warm water in a vat, which is then covered 
up. A small quantity of brewers' yeast is also added to aid 
in the fermentation. As soon as the mixture develops a 
slight heat, one part of fresh whey is added, and the fleshed 
skins entered into the tanning liquor in which they remain 
for about 12 hours. They are then tramped in the mixture 
so as to effect greater penetration, and left until the tanning 
process is complete. Whey is the milk fluid left after the 
casein and most of the fat have been removed from the 
milk by coagulation, and consists practically of a solution 
of all the milk-sugar or lactose, and the lactic acid of the 
milk, together with a small percentage of mineral salts, 
and a slight amount of fat. By fermentation, the milk- 
sugar is converted into lactic acid, which helps to effect 
the tan by swelling the skin. 

The effectiveness of the fermentation processes depends 
to a considerable degree on the action of certain bacteria 
and yeasts. Bacteria are one-celled organisms belonging to 
the vegetable kingdom, and some are so small as to be 
scarcely visible under a microscope, while some indeed can- 
not be seen by any means, their existence being inferred 
from their effects. As they vary in size, bacteria also vary 
in shape, some being spherical, others in the form of long, 
thin rods, while still others are of a spiral shape; another 



51 



FUR DRESSING AND FUR DYEING 

common form is the clumb-bell shaped bacterium. Some 
types are provided with what are known as flagella, which 
resemble fine hairs attached to the body of the organism, 
and which enable it to move about actively in liquids. The 
food of bacteria is always in liquid form, as only in this 
condition can it be absorbed. However, some kinds of bac- 
teria attack solid substances from which they obtain their 
nourishment, but this is done in an indirect way, by secret- 
ing certain fluids known as enzymes, which dissolve or 
digest the material and convert it into a form that can 
easily be absorbed by the bacteria. The enzymes are non- 
living chemical substances, which possess the peculiar prop- 
erty of bringing about the chemical change of an almost in- 
definite amount of material upon which they act, without 
themselves being in any way changed. Yeasts also act in 
a manner similar to the bacteria in causing various chemi- 
cal changes, particularly inducing fementations. In the 
simple " Schrot-beize," the starch contained in the bran or 
barley grains is first converted to a soluble sugar by means 
of enzymes secreted by the bacteria which are always 
present. This sugar then undergoes an acid fermentation, 
wdth the formation of lactic and acetic acids, due in this 
case to organisms known as the bacterium jur juris A and 
B. The action of the Russian tan is similar, but quicker. 
In this case, the sugar is already present in soluble form, 
and the yeast cells cause its fermentation with the produc- 
tion of lactic acid. In both cases, the acids as they form 
swell and loosen up the skin fibres slowly, the salt penetrat- 
ing between them, and keeping them separated on drying. 
Both methods give results which are equally good, but by 
the Russian tan the skins acquire a disagreeable odor, 
which makes this method of dressing objectionable. 

The lactic acid fermentation processes have an advan- 
tage over the pickle, in that the slow formation of weak 
organic acids with their gradual action produce a softer 
leather, with a gentler ' feel,' the presence of the flour and 

52 



TANNING METHODS 



the grains of the tan, aside from their tanning action, con- 
tributing to the fulhiess and softness of the leather. There 
is also less likelihood of the leather being subsequently af- 
fected by the presence of the acid in it, as lactic and acetic 
acids are much less injurious than sulphuric acid to leather. 
These disadvantages of the pickle can to a large degree, 
be overcome without any great difficulty. On the other 
hand, the matter of the length of time of the tanning 
process, shows the acid pickle at a great advantage, and 
so, especially for furs other than those obtained from sheep 
and goats, the pickle is in most cases used as the principle 
method of tanning. In Austria, Russia, and to a certain 
extent in Germany also, the " Schrot-beize " is still con- 
siderably employed, chiefly for dressing sheep and lamb 
skins. The dressing of the various kinds of Persian lambs, 
caraculs, astrachans, etc., in the native center of the in- 
dustry in Buchara and surrounding districts, is also a 
" Schrot-beize," barley, rice flour or rye flour, and salt water 
being used to prepare the skins, the manipulations being 
essentially the same as those described above, although 
carried out in cruder and more primitive fashion. 

2. Mineral Tans 

The basis of the tanning of furs by means of solutions 
of mineral compounds is the fact that the basic salts of 
certain metals are capable of producing leather. It has 
been found that compounds of aluminum such as alum or 
aluminum sulphate, or any other soluble neutral salt of 
aluminum, possess tanning powers. Other metals which 
are capable of forming salts of the same type are also en- 
dowed with the quality of converting skin to leather under 
suitable conditions, chromium and iron being the most im- 
portant metals in this connection. Chemically these 
metals all belong to the same group, and have properties 
which are very similar in many respects, the characteris- 

53 



FUR DRESSING AND FUR DYEING 

tic of most importance for tanning purposes being the 
quality of forming soluble basic salts by the addition of 
alkalies or alkaline carbonates to solutions of their neutral 
salts, or in certain instances simply by the action of water 
upon these neutral salts. By neutral salts are meant those 
in which the metallic content is combined with the nor- 
mal proportion of acid ; while basic salts are those in which 
the acidic portion is present in less than the normal ratio, 
being partially replaced by a hydroxide group. When the 
acid part of the salt has been entirely replaced in this way, 
the compound is called a hydroxide or hydrate of the metal. 
Between the neutral salt and the hydroxide several different 
basic salts are possible, some being soluble, while others are 
insoluble. If into a solution containing a basic salt of either 
aluminum, iron or chromium a skin be entered, a part of 
the basic salt will be precipitated on it in insoluble form. 
Inasmuch as neutral salts of these metals when dissolved in 
water split up to a small degree, into free acid and soluble 
basic salt, a skin immersed in such a solution will also ab- 
sorb the basic salt in an insoluble form. Upon these facts 
in general, depends the action of the mineral tans used in 
tanning furs. 

A. Alum Tan 

The alum tan is one of the oldest methods of producing 
leather, being employed by the Romans about two thou- 
sand years ago, and it is believed, by the Egyptians at a 
much earlier period. Its extensive use in Europe, however, 
dates from the time of the conquest of Spain by the Moors, 
who introduced the process. 

At the present time, rabbits and moles are tanned by this 
process, as are also at times other furs such as muskrats, 
squirrels, sables, martens, etc., when a better tan is desired 
than that produced by the pickle. Ordinary alum, which is 
a double sulphate of aluminum and potassium, and alumi- 
num sulphate are the chief compounds used for this tan. 

54 



TANNING METHODS 



In recent years, the aluminum sulphate has to a consider- 
able degree replaced the alum for tanning, inasmuch as it 
can be cheaply obtained in a sufficiently pure form, and 
contains about one and one-half times as much active 
aluminum compound as does alum. 

While the aluminum salt can be used alone for tanning, 
it produces a stiff, imperfect leather, so salt is always 
added. The ratio of the salt to the aluminum sulphate or 
alum can vary within rather wide limits, the mixtures used 
in practise ranging from one part of salt to four parts of 
the aluminum compound, up to equal parts of both, or even 
in some formulas, a greater proportion of salt than of the 
other constituent. Ratios which are most common are four 
of alum to three of salt, or two of alum to one of salt. 

When aluminum sulphate is dissolved in water, a small 
part of it splits up into a soluble basic salt and an equiva- 
lent amount of free acid. The reaction may be shown as 
follows : 

AL(S0,)3 + 2H3O = AL(S04).(OH)2 + H.SO^ 

aluminum water basic aluminum sulphuric 

sulphate sulphate acid 

When a skin is entered into such a solution, the free acid 
is absorbed, causing a swelling of the pelt. While this is 
taking place, a further quantity of the neutral aluminum 
salt splits up into more basic salt and free acid. At the 
same time the basic aluminum sulphate is also taken up 
by the skin, probably attaching itself to some of the acidic 
groups contained in the skin substance, in a manner analo- 
gous to the combination of the acid with the basic groups 
of the skin substance. A point is reached, however, when 
the skin is no longer able to take up more of the basic salt, 
for the presence of the acid undoubtedly acts as a deterrent. 
The skin, if dried after such a treatment contains a small 
amount of aluminum, which is insufficient to tan the pelt 
properly, and as a result this comes out in an undesirable 

55 



FUR DRESSING AND FUR DYEING 

and quite useless condition. If to the solution of the alumi- 
num sulphate salt is added, a different result is obtained. 
To a certain extent the salt acts here as in the pickle. The 
skin on absorbing the free acid of the solution naturally 
swells, but the salt reduces this swelling, and at the same 
time, by penetrating between the fibres and dehydrating 
them, produces a leather as in the pickle. In addition, the 
presence of the salt enables a greater amount of basic 
aluminum sulphate to be formed, and thus a greater quan- 
tity is taken up by the skin. On drying and stretching 
after such a treatment, a soft, flexible and stretchable 
leather is obtained. 

The number of formulas for tanning furs by this process 
is legion, the principle being the same in every instance, 
and mixtures of salt and alum or aluminum sulphate form 
the basis of the various tans. Following are a few 
typical formulas, which have been found to be of practical 
value : 

A solution is prepared by dissolving 7.5 lbs. of alum and 
3 lbs. of common salt in 20 gallons of water. When cool, 
the clean, fleshed skins are entered, being paddled or 
drummed for a short time and then allowed to remain 
until tanned. By this method the hair also takes up some 
of the alum, and if the skins are to be dyed, unevenness 
may result. In order to avoid this, the tanning may be 
effected by brushing a stronger solution on the pelt. A 
mixture of 4 lbs. of alum and 3 lbs. of salt, dissolved in 8 gal- 
lons of water, and made into a paste by the addition of 4 
lbs. of flour, is applied to the flesh-side of the skins. These 
are then placed in pairs, flesh-side together, and allowed 
to remain in a pile until tanned. Sometimes a second ap- 
plication is given. The flour may be omitted, but it serves 
to cause the tanning mixture to adhere better to the skins. 

Still another method is the following: Into the flesh of 
the moist, fleshed skins is rubbed a mixture of two parts 
of chy powdered alum with one part of salt. After allowing 

56 



TANNING METHODS 



time for it to be absorbed, another application is given, rub- 
bing in well, and especially treating the thick parts. The 
pelts are then folded up, or rolled together, flesh-side in, and 
placed in a vat or tub, which is covered up to prevent dry- 
ing. They are left so until tanned, as shown by examina- 
tion and test. They are then rinsed, hydro-extracted and 
dried, and after stretching and finishing, a soft, white, pli- 
able leather is obtained. 



B. Chroim Tan 

By using chrome alum instead of ordinary alum, to- 
gether with salt, skins can be tanned, but the leather formed 
is not altogether satisfactory. The basic principle here is 
the same as in the alum tan, depending on the formation 
of soluble basic chrome sulphates in the solution of a neu- 
tral sulphate. The method employed at the present time, 
the so-called one-bath process as distinct from the two-bath 
process, which cannot be applied for tanning furs, involves 
the production of the basic chrome sulphate by the addi- 
tion of an alkali or an alkaline carbonate to the solution of 
the neutral salt. It was Prof. Knapp who first published 
this process as early as 1858; but it was not until 1893 that 
it was shown to be of practical value, and was then patented 
in this country by Martin Dennis. Since that time it has 
been in general use with but slight modifications, i 

The chrome tan is used only to a limited extent in the 
tanning of furs, the method requiring very careful treat- 
ment and accurate supervision during the various stages of 
the process, and the leather coming out colored a pale-blue- 
green tint, which for some purposes is objectionable. In 
some plants ponies and rabbits are tanned with chrome; 
and when the skins are to be dyed by means of certain coal 
tar dyes, they have to receive a chrome tannage. The 
leather produced by a chrome tan is very durable, and pos- 
sesses great resistance to the action of water. 

57 



FUR DRESSING AND FUR DYEING 

Any salt of chromium, with either mineral or organic 
acids, can be used, but chrome alum is the one most com- 
monly employed. If a skin is entered directly into a solu- 
tion of a chrome salt made basic with an alkali, the precipi- 
tation of the insoluble basic salt will take place very rapidly, 
and the tanning will be only superficial. The procedure 
is therefore first to treat the skins with a chrome solu- 
tion which forms only small quantities of the basic salt. 
After the skins are impregnated with the solution, this is 
made basic, so that the real tan will take place within the 
skin tissues among the fibres of the corium. A common 
formula is the following: 5 lbs. of chrome alum are dis- 
solved in 10 gallons of water. The skins are entered into 
the solution at about 70° F. and paddled for about 2 hours, 
or drummed for one hour. Then a. solution of three pounds 
of washing soda is added slowly to the liquor which is then 
stirred up well, and the skins drummed or paddled again 
for an hour or two, and then left in the liquor for 12 to 24 
hours till completely tanned. The skins are rinsed, and 
washed in a 4% solution containing r,% of the weight of 
the skins of borax. The pelts are then well washed in clean 
water, hydro-extracted and dried. 

C. Iron Tan 

Tanning by means of iron salts has thus far been merely 
a matter of scientific interest and has not found any practi- 
cal use. The principle involved is identical with that of 
the preceding mineral processes. 

3. Chamois Tan 

The chamois dressing, as previously noted, is undoubt- 
edly the oldest method of preparing leather from skin, the 
various fat-containing substances derived from animals, 
fish, birds, etc., being used for the purpose. The chief ob- 
ject of the fat was to coat the fibres of the skin, thus pre- 

58 



TANNING METHODS 



venting their adhesion, and at the same time rendering 
them resistant to water. In the true chamois tan, the 
fat seems to have also a chemical function in contradistinc- 
tion to the other which is merely physical or mechanicaL 
For. if skins tanned by the chamois process be treated with 
a weak solution of an alkali, all the fatty materials should 
be removed thereby, but this happens only to a small ex- 
tent, the pelt retaining its softness and pliability, and the 
other characteristic qualities of leather, indicating that the 
fat is combined intimately with the skin substance in a 
permanent fashion. 

In tanning furs, various oils and fats are used, but not 
all are capable of producing a chamois tan. Among the 
fatty materials are mineral oils, and vegetable and animal 
oils and fats. Alineral oils are the distillation products 
of petroleum, partially liquid, and partially solid. Being 
inert substances, they have no tanning effect, but serve 
merely as water-proofing or fattening materials. Except 
for their oily nature they have nothing in common with 
fats, being quite unaffected by solutions of alkalies or of 
acids. 

Vegetable and animal fats and oils are, when pure, 
neutral substances formed by the combination of fatty acids 
with glycerine. They possess the property of saponifica- 
tion, that is. of forming a soap when treated with an alkali, 
the soap being the alkaline salt of the fatty acid. Under 
certain conditions, the fat can be split up into free fatty 
acid and glycerine by the action of acids, or even water 
alone. Some fats on long standing, split up in this way 
spontaneously in the presence of moist air. As a general 
rule, those fats which exhibit this property to a marked de- 
gree are affected by contact with the air, due to the ab- 
sorption of oxygen which reacts chemically with the fats, 
forming what are known as oxy-fatty acids, usually less 
soluble, and having a higher melting point than the original 
fats. Vegetable and animal fatty materials are classified 



59 



FUR DRESSING AND FUR DYEING 



on the basis of this phenomenon of absorbing oxygen from 
the air, those possessing this quality to a great degree be- 
ing called '' drying oils," others being '' partially drying," 
or "non-drying." Olive oil, castor oil, cocoanut oil and 
cottonseed oil are examples of non-drying or partially-dry- 




Fig. 8. Tramping Machine or " Kicker." 
{F. Blattner, Brooklyn, New York.) 

ing vegetable oils, linseed oil being the most important 
drying-oil in this class. Tallow, lard, butter-fat, neats-foot 
oil are non-drying animal fats, the drying oils being seal 
oil, whale oil, and cod-liver oil. 

For tanning purposes, this property of absorbing oxygen 
is important, because only with drying oils can a true 
chamois tan be obtained, non-drying oils acting like mineral 

60 



TANNING METHODS 



oils only as water-proofing materials. The details of the 
chamois process are not quite clear, there being considerable 
difference of opinion on the matter. But all the studies on 
the subject tend to prove that there are at least two phases 
to the process: first, the mechanical covering of the fibres 
with the fat, this property being common to all fats or oils 
which may be used; and second, the combination of the 
fat with the skin in some chemical way, as a result of the 
oxidation of the fat, a characteristic found only in the dry- 
ing oils. During the oxidation of the fats, the glycerine in 
them is converted to acrolein or acryl-aldehyde, which also 
aids the tanning. It was at one time supposed that the tan- 
ning action was due to this aldehyde alone, but a chamois 
tan can be made with fatty substances from which all the 
glycerine has been removed. The evidence on this question, 
however, is not quite conclusive. 

In general, the procedure of the chamois tan is as follows: 
The hydro-extracted, fleshed skins are rubbed on the flesh- 
side with a good quality of seal-oil. They are then folded 
up, and put into a ' kicker,' where they are tramped for 
two or three hours to work in the oil. The kicker is a 
machine such as shown in Fig. 8 consisting of a receptacle 
for the skins, and two wooden hammers which work up 
and down mechanically, turning and pounding the skins. 
(As many as 1000-1500 skins of the size of musk-rats can 
be worked at one time in such a machine.) The pelts are 
then taken out and hung up in a warm room for several 
hours, considerable oxidation taking place. Another coat 
of oil is then applied, which is again tramped in, and the 
skins are hung up once more and exposed to the air to 
cause the oil to oxidize. After the skins are sufficiently 
tanned they are rinsed in a weak soda solution to remove 
the excess oil, washed and dried. When skins with fine hair 
such as marten, sable, mink, etc., receive a chamois tan, 
they are not tramped in kickers as the delicate top-hair 
will be broken, and the value of the skin thereby reduced. 



61 



FUR DRESSING AND FUR DYEING 



Instead they are placed in small drums, together with metal 
balls of varying sizes and weights depending on the parti- 
ular fur treated, and the oil is worked in by rotating the 
drum. Such a ball-drum, as it is called, is shown in Fig. 9. 




Fig. 9. Ball Drum. 

(F. Blattner, Brooklyn, New York.) 

In conjunction with the chamois tan may be discussed 
the process of oiling, inasmuch as the method of application 
and the effect are both similar to the chamois tan up to a 
certain point. It is customary to treat skins tanned by any 
other method but the chamois process, with some oil in 
order to render them more impervious to water. The great- 
est variety of oils and fats can be used, the action in most 
cases being simply the mechanical isolation of the skin 
fibres by such a substance, thus corresponding to the first 

62 



TANNING METHODS 



or physical phase of the chamois tan. The chemical phase, 
if it takes place at all, is usually slight, and is merely in- 
cidental. Oiling is generally applied either before drying 
after tanning, or after drying, the oiled skins being placed 
in a kicker and tramped to cause the oil to penetrate. In 
some instances the oiling material is put in the same mix- 
ture as the tanning chemicals, and the tanning and oiling 
are effected simultaneously. 

Among fatty substances used for oiling are mineral oils, 
such as paraffine oil, and vaseline; animal fats, like train 
oils, butter, egg-yolk, glycerine, neats-foot oil; vegetable 
oils, like olive oil, castor oil, cottonseed oil; also sul- 
phonated castor oil and sulphonated neats-foot oil. These 
may be used singly or in various mixtures, an emulsion of 
an oil and a soft soap also being frequently employed. 

4. Formaldehyde Tans 

Formaldehyde has proven to be of great value in the tan- 
ning of furs, usually in conjunction with other processes. 
Formaldehyde is a gas with a strong, irritating odor, and its 
40% solution, which is the customary commercial form, also 
possesses this quality. When skins are treated for several ^ 
hours with a very dilute solution of the commercial product, 
a leather is obtained which combines the properties of the 
alum tan and the chamois tan. Moreover, in the majority 
of observed cases, where furs have been tanned with for- 
maldehyde, the skins seem to acquire a certain immunity 
to the attacks of vermin and moths. Although the skins do 
not in any way retain the odor of the formaldehyde, never- 
theless these destructive agents seem to be repelled. 

Numerous processes have been devised which use for- 
maldehyde in connection with other substances for tan- 
ning. Thus in a German patent is described a method in- 
volving the alternate or simultaneous treatment of pelts 
with solutions of formaldehyde and alpha or beta naphthol. 

63 



FUR DRESSING AND FUR DYEING 

Both the formaldehyde and the naphthol exercise tanning 
actions, but the process is not used in practise. 

In 1911, Stiasny, a well-known leather chemist produced 
a synthetic substance by the condensation of formaldehyde 
with a sulphonated phenol, forming an artificial tannin. 
This chemical, called " Neradol D," exhibits many of the 
properties characteristic of true tannins, although in no 
way related by structure and composition. By the use of 
" Neradol D " a soft, white and flexible leather is obtained, 
and it is therefore a suitable tanning material for furs. 

5. Combination Tans 

In many instances more than one method is employed in 
tanning the furs, and in this way what is known as a com- 
bination tan is produced. While the various individual 
processes described give more or less satisfactory results by 
themselves, they generally possess some features, which for 
certain purposes may be undesirable, and which can be elim- 
inated or considerably reduced by using other processes at 
the same time or subsequently. Some of the combination 
methods are, pickle with chrome tan, alum tan with chrome 
tan, and formaldehyde tan with pickle, mineral tan or 
chamois tan. By means of such combinations various 
qualities of tanned furs can be obtained, and if it is desired 
to produce a pelt having certain special characteristics, this 
can be brought about by combining two or more standard 
methods. 

Some illustrations of combined tannages are the follow- 
ing: Alum-chrome tan. The skins are tanned by the regular 
alum process, then the constituents of the chrome tan are 
dissolved directly in the same bath, and the chrome tan is 
effected as usual. Chrome-formaldehyde tan. To the regu- 
lar chrome tan solution is added Uh. of formaldehyde for 
every 10 gallons of chrome liquor. The rest of the process 
is as ordinarily. 

64 



TANNING METHODS 



6. Vegetable Tans 

In practise, the vegetable tanning matters are not used 
for furs, although in some special instances gambler cutch 
may be employed occasionally with some other tan. How- 
ever, many of these tannins also have dyeing properties, 
and are used in dyeing the furs. In this connection it must 
be mentioned that furs dyed with these materials also re- 
ceive a vegetable tan, which improves the quality of the 
leather to a considerable extent. 



Comparison of The Various Tanning Methods 

In choosing a method for tanning any particular kind of 
fur, several factors must be considered. The nature of the 
pelt, insofar as it is weak or strong; the time, labor and 
cost of materials required by the tanning process ; the effect 
on the leather of the different dyes and chemicals used in 
dyeing, if the skin is to be dyed, are a few of the points re- 
quiring attention and consideration. 

For furs which are only to be dressed, a simple tan like 
the pickle will suffice in most cases. Special instances, such 
as the rabbit and mole already mentioned, and a few other 
furs are tanned by the alum method. The pickle is un- 
doubtedly the cheapest and simplest method of tanning 
skins, and yields a soft, white leather which is permanent 
as long aa it is kept dry. If it is put into water, about 25% 
of the salt contained within the pelt dissolves out, and the 
acid present swells up the tissues. If the skin is dried in 
this condition, it will come out hard and brittle, tending to 
crack very easily. By treating the leather before drying with 
a strong salt solution, a good deal of the extracted salt will 
be replaced, and on drying and stretching, it will work out 
soft. Skins tanned by the " Schrot-beize " are affected by 
water in quite the same manner as the pickled skins. 

The alum tan gives a leather similar to that produced by 

65 



FUR DRESSING AND FUR DYEING 

the pickle, but with the advantage that the skins possess 
greater stretch and flexibility. In its resistance to water, 
the alum-tanned pelt is quite as susceptible as the other. 
As a general rule, the skin absorbs about 6% of its weight 
of alum from the tanning solution, but gives up three- 
quarters of this when it is soaked in water, produc- 
ing on drying, a hard, stiff leather. The chrome tan is 
especially impervious to water, easily resisting temperatures 
of 80° C, and even boiling water. It is employed to only a 
limited extent on account of the special effort and care re- 
quired to obtain satisfactory results, also because the pelt 
acquires a pale blue-green color which is not desired on 
dressed skins. The chamois tan, and some of the combina- 
tions of the formaldehyde tan with the other methods, give 
very soft, flexible leathers which possess a sufficiently great 
resistance to the effects of water and heat. 

In tests made to determine the best working tempera- 
tures for dyeing skins dressed by the salt-acid tan, and for 
skins dressed by the chamois process, some very interesting 
facts were brought out. These two tans were chosen be- 
cause they represent opposite extremes, the salt-acid tan 
usually giving the poorest results, and the chamois tan 
giving the best results in practise in dyeing. Other 
methods, except the chrome, range between these two. The 
procedure in these experiments was to treat the skins at 
ordinary temperatures in water, or dilute solutions of the 
various chemicals and dyes usually employed in dyeing, 
and then heat these solutions until the leather just began 
to shrink and shrivel up. This point, called the shrinking 
point (S.P.), gave the temperature to which the skins could 
be subjected in the given solution without danger to the 
pelt. (The experiments and observations were made by 
Erich Schlottauer, while director of a large German fur 
dressing and dyeing plant). 

The first observation made was that different furs tanned 
by the same process were affected differently in the same 

66 



TANNING METHODS 



solutions. Thus in plain water, three furs, all tanned by the 
acid-salt tan, had shrinking points varying by several de- 
grees; similarly with two different furs tanned by the 
chamois process, there was a variation in the shrinking 
point of two degrees. The explanation of this discrepancy 
among the different skins may be that there was a slight 
difference in the conditions under which they were tanned, 
experiments showing that a maximum difference of 4°C, 
may exist among skins tanned by the same process, but 
not under the same or identical circumstances. Another 
reason for the variation may be the fact, that some skins 
are more greasy than others, and are thus more resistant 
to the effects of water or of some chemicals. The furs with 
the higher shrinking points in water were those which 
naturally are more greasy than the others. 

Weak solutions of acids tend slightly to lower the shrink- 
ing point, while weak solutions of alkalies appreciably 
raise it, in both chamois-tanned and salt-acid-tanned skins. 
Solutions of dyes and mordants as a general rule increase 
the resistance of the skin to heat, varying quantities of 
these substances having no, or little different effects on the 
shrinking points. Previous treatment of the leather with 
some oil considerably raises the shrinking point of the 
pelt. Formaldehyde effects a great increase of the resist- 
ance of the skins to heat, especially with chamois-tanned 
furs. The experiments in this case were made by first treat- 
ing the skins in the weak formaldehyde solution, and then 
determining the shrinking point in plain water. 

Two skins, both dressed by the " Schrot-beize," a Persian 
lamb and an astrachan, after dyeing had shrinking points 
almost 10 degress higher than when undyed. The extra 
tannage which the skins received from the tannins used in 
the dye mixtures for these furs, accounts for this increased 
resistance to heat. 

The following tables give the observed figures in the 
different experiments: 



67 



FUR DRESSING AND FUR DYEING 



Table I 



Salt-acid Tan 
Australian Opossum . 

Marmot 

Skunk 



Chamois Tan 



Mink . . 

Muskrat 



A 


B 


C 


S.P. 


S.P. 


S.P. 


C. 


C. 


C. 


46° 


58° 


45° 


45° 


50° 


42° 


47° 


56° 


43° 


52° 


61° 


45° 


50° 


58° 


42° 



A — Water 

B — Water plus 1% Ammonia (s.g. 0.910) 

C — Water plus 1% Sulphuric acid (66° Beaume) 



Table II 





A 

S.P. 


B 

S.P. 


C 

S.P. 


Salt-acid Tan 
Australian Opossum 

Chatnois Tan 
Mink 


C. 

53° 

59° 


C. 
52° 

59° 


C. 

54° 

59° 



A — 1000 CO. water plus 40 c.c. Peroxide plus 5 c.c. ammonia 
B — 500 c.c. water plus 2 grams Ursol D (Para-phenylene- 

diamine) 
C — 500 c.c. water plus 5 grams Ursol D 



68 



TANNING METHODS 



Table III 





A 


B 


C 


D 




S.P. 


S.P. 


S.P. 


S.P. 


Salt-acid Tan 


C. 


C. 


C. 


C. 


Australian Opossum . . 


51° 


51° 


53° 


56° 


Chamois 










Mink 


59° 


59° 


61° 


62° 



A — 500 c.c. water plus 5 grams ground nut-galls 
B — 300 c.c. water plus 2 grams pyrogallic acid 
C — 500 c.c. water plus 2 grams potassium bichromate 
D — Water, after treating leather with rapeseed oil 

Table IV 





A 


B 


C 


D 




S.P. 


S.P. 


S.P. 


S.P. 


Salt-acid Tan 


C. 


C. 


C. 


C. 


Australian Opossum . . 


49° 


49° 


55° 


50° 


Chamois Tan 










Mink 


59° 


67° 


69° 


70° 



A — 500 c.c. water plus 5 c.c. formaldehyde for 1 hour 
B — 500 c.c. water plus 5 c.c. formaldehyde for 12 hours 
C — 500 c.c. water plus 10 c.c. formaldehyde for 3 hours 
D — As in C, but treated with 500 c.c. water plus 5 c.c. 
ammonia, instead of water alone. 

Table V 





A 

S.P 


B 

S.P. 


Persian Lamb 

Astrachan 


C 

44° 

47° 


C 

54° 
55° 



A — Before dyeing 



B — After dyeing 



69 



FUR DRESSING AND FUR DYEING 

As a result of these experiments it may be concluded 
that the maximum temperature for drying salt-acid tanned 
skins should be 40° C, while for chamois tanned skins the 
temperature may be permitted to reach 45° C. without any 
danger of the leather being affected. Moreover, in the case 
of pickled skins, the matter of extraction of the tanning 
agent, as well as that of the leather becoming " burned " 
may be effectively counteracted by brushing some oil or 
fat on to the leather side before dyeing the pelt. 

The shrinking points of skins dressed by the various tan- 
ning methods are constant within certain limits, depending 
on the nature of the skin and on the conditions of tanning, 
and it is possible by observing the shrinking point, in con- 
junction with other characteristics of a given pelt, to de- 
termine what method of tanning was used. 



70 



CHAPTER VI 
FUR DRESSING 

Drying and Finishing 

ONE of the most important operations of all the 
fur dressing processes is the drying of the skins. 
For even when all the previous steps have been 
successfully completed, there is still a great possibility of 
the skin being injured if the drying is not properly and 
carefully carried out. 

The essential requirements for good drying are proper 
temperature, uniformity and rapidity. The leather part 
of the fur cannot, in the moist state, resist temperatures ex- 
ceeding about 45° centigrade, for when dried, the skin turns 
out hard and stiff, and cracks easily. The furs must there- 
fore be dried at an initial temperature of 25° to 30° centi- 
grade, and as the moisture is gradually removed, the tem- 
perature may be raised, for the less water that remains in 
the pelt, the less is the leather affected by the heat, and the 
more difficult is the removal of its aqueous content. 

If the drying process is not a uniform one, that is, if 
all the skins in a lot are not subjected to the same drying 
conditions, then after the drying has proceeded for a cer- 
tain time, some skins may be quite dry while others are 
not, or there may be as many different degrees of dryness 
as there are skins drying. There is also the possibility of 
great variation in the amount of moisture removed from 
chfferent parts of the same skin. Such a state of affairs re- 
quires an extra expenditure of time, labor and heat power 
in order to get the whole lot of furs into a more or less uni- 
form condition. Moreover in some kinds of furs, especially 

71 



FUR DRESSING AND FUR DYEING 

those with thick skins, when the drying is not even, there is 
danger of the epidermal layer drying away from the corium, 
and subsequently peeling and cracking. Uniformity of dry- 
ing requires the maintenance of a reasonably constant tem- 
perature equally distributed throughout all parts of the 
space where the drying is done, so that all the furs may be 
dried under the same conditions. 

Rapidity of drying is desirable not only because it is 
beneficial to the condition of the pelt, but also from the 
point of view of practical business economy. The space 
occupied by the drying should be as small as possible com- 
patible with the volume of work, and with the efficiency 
of operation. Slow drying involves the use of much space 
to take care of all the skins to be dried, or an accumula- 
tion of pelts ready to be dried, neither of which conditions 
is efficient or desirable. 

It was formerly the general custom, still practised in 
some establishments, to dry the skins by hanging them up, 
leather-side out on lines in a large room or loft, the heat 
being usually supplied by steam pipes. Such a procedure 
occupied often as long as two or three days to get complete 
drying, involved a great deal of labor, and the results were 
far from uniform. In fact, in order to get the skins more 
nearly equable, it was necessary to subject them to an 
additional operation. This usually consisted of rotating the 
skins in a closed drum for several hours, the constant inter- 
mingling of the pelts in contact with each other causing any 
moisture left in them to be evenly distributed throughout 
the whole lot. The skins, by this process also are rendered 
somewhat softer and more flexible, but by drying under 
proper conditions the entire extra operation can be dis- 
pensed with, the furs coming out quite as soft and flexible 
without the drumming. 

A great improvement was the adoption of large fans to 
circulate the heated air in the loft, thereby approaching 
more nearly an even temperature. More modern devices 

72 



DRYING AND FINISHING 



have, however, been developed, whereby drying can be 
effected in the most uniform manner, with perfect control 
of temperature, and requiring the least possible consump- 
tion of space, time, labor and power. A typical arrange- 
ment consists of a large closed chamber, generally con- 
structed of steel, and divided into several compartments 
each of which may be operated independently of the others. 
Air, heated over suitably located steam pipes to the re- 
quired temperature, is forced through the various com- 
partments by means of fans operated by power. The con- 
ditions may be varied in each compartment, as to tempera- 
ture or humidity, both of which can easily be regulated, or 
all the compartments may be used together as one unit. 
The skins are hung up on rods or lines in the compart- 
ments, or on special frames for the purpose, which are then 
entered into the compartments and the doors shut. The 
dry, heated air is forced to pass over the skins, and takes 
up their moisture. At the further end of the drying cham- 
ber is another fan which removes the moisture-laden air 
after it has done its work. The drying is effected in from 
6 to 24 hours, and all skins are obtained in the same condi- 
tion, for the process is quite uniform and regular. 

Within recent years there has been evolved a highly 
efficient and economical drying equipment, based on a 
samewhat different principle than underlies any of the 
foregoing methods. The conveyor type of dryer, as it is 
called, is admirably suited to the needs of the fur dressing 
and dyeing industry, and is undoubtedly superior to any 
of the previous systems of drying furs, in that it affords 
an enormous saving of space, time, labor and power, and 
gives greater uniformity and presents better working con- 
ditions. 

The conveyor dryer consists essentially of a steel enclo- 
sure, through which the skins pass on horizontal conveyors. 
Where special insulation is necessary, asbestos panels are 
used to line the enclosure, making the dryer absolutely 



73 



FUR DRESSING AND FUR DYEING 



fireproof, and enabling the maximum utilization of heat. 
In the middle of the dryer are located the steam coils which 
furnish the heat, and in many instances exhaust steam can 



rT^VT^. 





Q 



Z w s 

O > := 



5 z . 

a 

> •- -?^ 

S s § 



be used as the source of heat. Figure 10 shows diagram- 
matically the arrangement and operation of the conveyor 
type of dryer. The enclosure is divided into several com- 



74 



DRYING AND FINISHING 



partments, in each of which a different condition of tem- 
perature and humidity is maintained, the temperature be- 
ing closely and accurately regulated by an automatic 




control, and once the dryer has been set for any condition, 
all skins will be dried exactly the same, regardless of 
weather or season. 

75 



FUR DRESSING AND FUR DYEING 

The skins to be dried are placed on poles which in turn are 
set on the horizontal conveyors as in Fig. 11. As the skins 
pass through the compartments, large volumes of air, heated 
to the required temperature over the steam coils, are cir- 
culated among the skins by means of the fans. Exhaust 
fans, properly placed, remove a certain quantity of mois- 
ture-laden air when it has accomplished its full measure of 
work. When the skins on the conveyors have passed the 
full length of the dryer, they are entirely dry, and are then 
removed from the poles. (Fig. 12). The time required 
for drying varies according to the nature of the fur from 
1-2 hours to 6-8 hours. In tests made to determine the 
relative efficiency of the conveyor type of dryer as against 
the old " loft " method, it was found that there was a saving 
of over 50% in power, and of 85% in floor space, as well 
as a great saving of labor, when the conveyor system was 
used, the number of skins dried in a given period of time be- 
ing the same in both cases. The advantages of the new 
method are easily apparent, and the saving is sufficiently 
great with large lots of furs, to make an appreciable differ- 
ence in the final cost of dressing. 

If the skins have been dried by a modern drying system 
they all come out in a uniform condition, and are ready to 
go on immediately to the next operation. If, however, a 
form of the " loft " method of drying has been used, it is 
customary to subject the skins to an additional process. 
The dried pelts are put in drums with damp sawdust, and 
drummed for a short time in order to get them into the 
proper condition. The drumming is essential for the pur- 
pose of equalizing the condition of the pelts, some being 
drier than others, and as a consequence of the contact with 
the moist sawdust, they are all brought to the same degree 
of dryness. As a result of this operation also, the skins be- 
come considerably softened. 

Then if the pelts have not been previously oiled during 
the tanning process, or prior to the drying, they receive this 

76 



DRYING AND FINISHING 



treatment now. The oil or fat is applied to the leather side 
of the furs, which are then placed in the tramping machine 




for a short time in order to cause the oil to be forced into the 
skin. The fibres of the corium thus become coated with a 
thin layer of fatty material, which contributes greatly to 

77 



FUR DRESSING AND FUR DYEING 

the softness and flexibility of the pelt, and increases its 
resistance to the action of water, and also, in certain in- 
stances a partial chamois tan is produced, thereby improv- 
ing the quality of the leather. 

The skins are now returned to the work bench, and sub- 
jected to the stretching or " staking " process. This con- 
sists in drawing the skin in all direc- 
tions over the edge of a dull blade, 
which is usually fixed upright in a 
post with the edge up. Or, the 
stretching may be done on the 
fleshing bench, substituting a dull 
blade for the fleshing knife. Re- 
cently staking machines are being 
used in the larger establishments, 
the work being done much more 
quickly and efficiently. As a result 
of this operation, the leather be- 
comes very soft and flexible, every 
bit of hardness and stiffness being 
eliminated, and the skins receive 
their maximum stretch, thereby giv- 
ing the greatest possible surface to 
the pelage. This not only helps to 
bring out the beauty of the hair, but 
is also a decided advantage from the 
Fig. 13. Stretching economic point of view, as a con- 
Machine for Cased Skins giderable Saving of material is effect- 

(Reliable Machine Worlcs, i • ^i • j.- ^4-^ 

Evergreen, L. I.) ^^^ "^ ^^^^^ ^^3"' sometmies even to 

the extent of twenty-five per cent. 
Cased skins are stretched in a somewhat different manner, 
by means of stretching irons. These consist of two long 
iron rods joined by a pivot at one end. The skins are 
slipped on to the irons, which are then spread apart, and 
in this way the skins are stretched and softened. A machine 
which does this work very efficiently is shown in Fig. 13. 

78 




DRYING AND FINISHING 



The skin is drawn onto the stretching arms, in this case 
made of bronze, which are then forced apart by pressing on 
a pedal. When properly stretched to the maximum width 
in all directions possible, and thus thoroughly softened, the 




Fig. 14. Fur Beating Machine. 
(S. M. Jacoby Co., New York.) 

skin can easily be reversed, that is, turned hair-side out. As 
many as 6000 skins can be stretched, or 4000 to 5000 skins 
stretched and reversed by one man in one day on such a 
machine. 

The pelts are then combed and beaten. In smaller 
plants these operations are done by hand, but suitable 

79 



FUR DRESSING AND FUR DYEING 



machines are being employed. In order to straighten out 
the hair, it is combed or brushed. Then in order to 
loosen up the hair, and to cause it to display its fullness, the 
furs are beaten. This process is also done by hand in some 
establishments, but up-to-date places use mechanical de- 
vices for this purpose. A type of machine which has proven 
very successful, and is enjoying considerable popularity is 
shown in Fig. 14. These machines are also made with 
special suction attachments which remove all dust as it 
comes out of the beaten skin, thereby making this formerly 
unhealthful operation thoroughly sanitary and hygienic. 

The final process is drum-cleaning. This operation is 
intended specifically for the benefit of the hair part of the 
fur, and is very important inasmuch as the attractive ap- 
pearance of the fur depends largely upon it. The drum, 
such as is shown in Fig. 15 is generally made of wood, or 
sometimes of wood covered with galvanized iron. The skins 
together with fine hardwood sawdust are tumbled for 2 to 4 
hours, or sometimes longer. Occasionally a little asbestos or 
soapstone is added to the sawdust; for white, or very light- 
colored skins, gypsum or white sand is used, either alone, or 
in admixture with the sawdust; and for darker skins, 
graphite or fine charcoal is sometimes added in small quan- 
tities. The drum-cleaning process polishes the hair, giving 
it its full gloss and lustre, and at the same time absorbing 
any oil or other undesirable matter which may be adhering 
to the hair as a result of the washing and tanning processes. 
Any soap, or traces of mordant are wiped off and so re- 
moved, and by using heated sawdust, or heating the drum 
while rotating, the fur acquires a fullness and play of the 
hair which are great desiderata in furs. The sawdust must 
then be shaken out of the furs. This is done by cageing. 
In some instances, the drum itself can be converted into a 
cage, by replacing the solid door with one made of a wire 
screen. (Fig. 16.) Usually, however, the skins are removed 
from the drum and put in a separate cage, which is built 

80 



DRYING AND FINISHING 



like the drum, but has a wire net all around it, through 
which the sawdust falls, while the skins are held back. 
The cages are generally enclosed in compartments in order 
to prevent the sawdust from flying about and forming a 
dust which would be injurious to the health of the workers. 




Fig. 15. Drum. (Combination Drum and Cage as a Drum) 
{F. Blattner, Brooklyn, New York.) 

In large establishments, the drum-cleaning machinery occu- 
pies a large section of the plant, many drums and cages 
being used, and special arrangements being made to take 
care of the sawdust which can be used over again several 
times, until it becomes quite dirty. 

With this operation ends the ordinary procedure of fur 
dressing. But there are several additional processes re- 
quired in the treatment of certain furs, which are generally 

81 



FUR DRESSING AND FUR DYEING 



undertaken by the dresser, and chief among these are shear- 
ing and unhairing. Sometimes this work is done in separate 
establishments organized solely for this business. Certain 




Fig. 16. Cage. (Combination Dri^m and Cage as a Cage.) 
(F. Blattner, Brooklyn, New York.) 

kinds of furs, among them being seal, beaver and nutria, 
possess top-hair which may detract from the beauty of 
the fur. the true attractiveness being in the fur-hair. The 
top-hairs are therefore removed, and for this purpose 
machines are now being used. Formerly this work was all 
done by hand, and on the more expensive furs like seal 
and beaver, unhairing is now done on a machine operated 
by hand. The principle of the process is as follows: The 
skins are placed on a platform and the hair blown apart by 

82 



DRYING AND FINISHING 



means of a bellows. The stiff top-hairs remain standing up, 
and sharp knives are brought down mechanically to the de- 
sired depth, and the hair is cut off at that point. The skin 




Fig. 17. Unhairing M.\chine. 
(Seneca Machine & Tool Co., Inc., Brooklyn, N. Y.) 

is then moved forward a short distance, and the process re- 
peated until all the top-hairs have thus been cut out. With 
muskrats, or other pelts which do not require such very 
careful attention, the whole process is done automatically 
on a machine. The fur-hair is brushed apart by means of 
brushes and a comb, and at regular intervals, sharp knives 
cut off the top-hairs. Several hundred skins can be un- 
haired in a day on such a machine requiring the atten- 
tion of only one man. A machine for unhairing skins is 
shown in Fig. 17. 

With other furs, such as rabbits, hares, etc., where the 
trouble of unhairing would be too great commensurate with 

83 



FUR DRESSING AND FUR DYEING 

its advantages, the hair is sheared instead. The top hair is 
cut down to the same length as the under-hair by means of 




Fig. 18. Fur-Shearing Machine. 
(Seneca Machine & Tool Co., Inc., Brooklyn, N. Y.) 

shearing machines which can be regulated to cut to any de- 
sired length of hair. A typical device for shearing furs is 
shown in Fig. 18. 



84 



CHAPTER VII 
WATER IN FUR DRESSING AND DYEING 

THE assertion has often been made, although its 
absurdity is now quite generally realized, that the 
success of the European fur dressers and dyers, 
particularly in Leipzig, is due to the peculiar nature of the 
water used, which is supposed to be especially suited for 
their needs. The achievements in this country in the fur 
dressing and dyeing industry during the past few years 
are ample and sufficient answers to the claim of foreign 
superiority in this field no matter what reason maybe given, 
and particularly when the quality of the water used is ad- 
vanced as a leading argument. For the water employed 
by the establishments in and about New York, as well as 
in other sections of the country is surely not the same as 
the water of Leipzig, yet the work done here is in every re- 
spect the equal of, if not better than the foreign products. 

It is interesting to note that similar rumors were cur- 
rent here in the early period of the development of the 
American coal-tar industry since 1914. Our efforts to estab- 
lish an independent dyestuff industry were doomed to fail- 
ure, according to those who circulated the stories, because 
we did not have the water, which they claimed was respon- 
sible for the German success. The present status of the 
American dye business, in its capacity satisfactorily to 
supply most of the needs of this country and of others as 
well, speaks for itself. 

However, as is often the case with such erroneous asser- 
tions, there is just enough of an element of truth in the 
statement regarding the peculiar qualities of certain kinds 
of water, to make the matter worthy of consideration. 

85 



FUR DRESSING AND FUR DYEING 



Water is certainly a factor of great importance in fur 
dressing and dyeing, and it is not every sort of water that 
is suitable for use. This fact was recognized by the early 
masters of the art. for they invariably used rain-water as 
the medium for their tanning and dyeing materials, and 
their choice must be regarded as an exceedingly wise one. 
While the necessity for giving consideration to the quality 
of the water for fur dressing purposes is great, it is in fur 
dyeing that the effects of using the wrong water are largely 
evident, and so extra care must be exercised in the selection 
of water for this purpose. 

The essential requirements for a water suitable for the 
needs of the fur dressing and dyeing industry, are: first, a 
sufficient, constant and uniform supply; and second, the ab- 
sence of certain deleterious ingredients. Chemically pure 
water is simply the product of the combination of two parts 
by volume of hydrogen with one part by volume of oxygen. 
Such water can only be made in the laboratory, and is of 
no importance in industry. For practical purposes, dis- 
tilled water may be regarded as the standard of pure water. 
Here, too, the cost and trouble involved in the production 
of distilled water on a large scale is warranted only in 
a certain few industrial operations. A natural source of 
water which in its character most nearly approaches dis- 
tilled water is rain. In fact, rain-water is a distilled water, 
for the sun's heat vaporizes the water from the surface of 
the earth forming clouds, which on cooling, are condensed 
and come down as rain. Rain-water is usually regarded 
as the purest form of natural water. Exclusive of the first 
rain after a dry period, rain-water is quite free of impuri- 
ties, except possibly for a small percentage of dissolved at- 
mospheric gases, which are practically harmless, and which 
can usually be readily eliminated by heating the water. 
Moreover, rain-water is quite uniform in its composition 
throughout the year in the same locality, and it possesses all 
the desirable qualities of a water suited for fur dressing and 

86 



WATER IN DRESSING AND DYEING 

dyeing purposes. Formerly when the quantity of water 
used in the industry was comparatively small, the supply 
from rain was sufficient to meet all the requirements. But 
now, when tremendous quantities of water are used con- 
stantly, rain-water is no longer a feasible source, and other 
supplies must be utilized, although in a sense, all water 
may be traced to rain-water as its origin. 

When rain-water falls on the earth it either sinks into 
the ground until it reaches an impervious layer, where it 
collects as a subterranean pool, forming a well, or continues 
to flow underground until it finally emerges at the surface 
as a spring; or on the other hand the rain-water may sink 
but a short distance below the surface, draining off as 
ponds, lakes or rivers. In the first case the water is called 
ground water, in the latter it is known as surface water. 
Ground water usually contains metallic salts in solution, 
and relatively little suspended matter. If the water has 
percolated through igneous rocks, like granite, it may be 
quite free even of dissolved salts, and such water is 
considered " soft." If, however, the rocky formations over 
which, or through which, the water has passed contain lime- 
stone or sandstone, or the like, salts of calcium and mag- 
nesium will be dissolved by the water. The presence of the 
lime and magnesia salts, as well as salts of aluminum and 
iron, in the water, causes it to be what is termed " hard." 
Surface water is more likely to contain suspended matter, 
with very little of dissolved substances. Suspended matter, 
like mud, contains much objectionable matter such as 
putrefactive organisms and iron, but most of these materi- 
als can be removed by filtration or sedimentation, and sel- 
dom cause any difficulties. 

Hardness in water is generally the chief source of trouble 
when the water is at fault. Hardness may be of two kinds, 
either permanent, or temporary, or sometimes both are 
found together. Water which is permanently hard usually 
contains the lime and magnesia combined as sulphates. 

87 



FUR DRESSING AND FUR DYEING 

Temporary hardness, on the other hand, is due to the pres- 
ence of hme and magnesia in the form of bicarbonates, the 
carbon dioxide contained in the water having dissolved the 
practically insoluble carbonates: 

CaCOa + CO. + H,0 = Ca(HC03)2 

calcium carbon water calcium 

carbonate dioxide bicarbonate 

Temporary hardness can be eliminated by heating the 
water, the carbon dioxide being expelled and the carbonates 
of lime and magnesia being precipitated and then filtered 
off. Both permanently and temporarily hard waters can 
be softened by the addition of the proper chemical, such as 
an alkaline carbonate like sodium carbonate. This precipi- 
tates insoluble carbonates of the lime, magnesia, iron and 
aluminum, leaving a harmless salt of sodium in solution in 
the water. The sludge is allowed to settle in tanks before 
the water is used. 

In fur dressing and dyeing, water is employed for soaking 
and washing the skins, dissolving chemicals, extracts and 
dye materials, and also for steam boilers. A small amount 
of hardness in the water is not harmful, and up to 10 parts 
of solid matter per 100,000, may be disregarded. Perma- 
nent harchiess is particularly objectionable in water for 
boiler purposes, as it forms scale. The effect of the impuri- 
ties of the water depends on the nature of the chemicals and 
dyes used. Where acids are used in solution compounds of 
magnesium, lime and aluminum will generally not interfere. 
Hard water must not be used for soap solutions, as sticky 
insoluble precipitates are formed with the soap by the 
metals, this compound adhering to the hair, and being diffi- 
cult to remove, will cause considerable trouble in subsequent 
dyeing. An appreciable loss of soap also results, as one part 
of lime, calculated as carbonate will render useless twelve 
parts of soap. In tanning or mordanting, where salts of tin, 
aluminum or iron are employed, hard water should not be 

88 



WATER IN DRESSING AND DYEING 

used, as lime and magnesia will form precipitates with 
them. Bichromates will be reduced to neutral salts, and 
cream of tartar will also be neutralized. With dyes also, 
hard water has a deleterious effect. Basic dyes are precipi- 
tated by this kind of water, rendering part of the dye use- 
less, and also causing uneven and streaky dyeings. Some- 
times the shades of the dyeings are modified or unfavorably 
affected. Considerable quantities of lime and magnesia in 
the water will cause duller shades with logwood and fustic 
dyeings. The presence of iron, even in very slight quanti- 
ties generally alters the shade, darkening and dulling 
the color. 

These facts were apparently all recognized and under- 
stood by the fur dressers and dyers of an earlier period, for 
instead of utilizing the water of lakes and streams near at 
hand, which afforded a more constant supply, but which 
contained harmful impurities, they collected the rain-water, 
which was always soft. Whether they realized the nature 
and character of the substances that make water hard is 
uncertain, but they were always careful to avoid such water. 
At the present time establishments located in and about 
large cities like New York, where the majority of American 
fur dressing and dyeing plants are situated, have no trouble 
about the water. The cities supply water which is soft, 
suitable alike for drinking and industrial purposes. Other 
plants, not so fortunately situated, often have to employ 
chemical means to treat the water so as to make it suitable 
for use. 



89 



CHAPTER VIII 
FUR DYEING 

Introductory and Historical 

IN discussing fur dyeing, the question naturally arises, 
" Why dye furs at all? Are not furs most attractive 
in their natural colors, and therefore more desirable 
than those which acquire their color through the artifices 
of man?" The answer cannot be given simply. Natural furs 
of the more valuable kinds are indeed above comparison 
with the majority of dyed furs. Yet there are several rea- 
sons which fully justify and explain the need for fur dyeing, 
for at the present time, this branch of the fur industry is 
almost as important and indispensable as the dressing of 
furs. 

The first application of dyeing to furs, had for its pur- 
pose the improvement of skins which were poor or faulty 
in color; or rather, the object was to hide such defects. As 
nearly as can be ascertained, this practise was instituted 
at some time during or before the fourteenth century, for 
fur dyeing seems to have been common during that period^ 
as is apparent from the verses of a well-known German 
satirist, Sebastian Brant, who lived in the latter part of 
the fourteenth century: 

" Man kann jetzt alles Pelzwerk fiirben, 
Und tut es auf das schlechste gerben." 

However, at a later period, there was a general condemna- 
tion of the dyeing of furs, and among the list of members 
of the furrier's guilds, none can be found who are described 

90 



FUR DYEING — INTRODUCTORY 

as dyers. There is a record of a decree issued by a prince 
in a German city in the sixteenth century, prohibiting the 
practise of fur dyeing. Inasmuch as furs were worn only 
by the nobility and certain other privileged classes, and 
also were very costly, there was great profit to be had by 
dyeing inferior skins so as to disguise the poor color, and 
then selling such furs at the price of superior quality skins. 
This was undoubtedly the reason for the prohibitory de- 
cree, but there were some who continued to practise the 
forbidden art in secret, using secluded and out-of-the-way 
places for their workshops, and mixing their carefully- 
guarded recipes with as much mystery as the witches did 
their magic potions. These circumstances probably ac- 
count for the great amount of mystery which has been, and 
still is to a considerable degree, attached to fur dyeing, 
and also explains the opprobrium and distrust with which 
fur dyers were formerly regarded. 

Even at the present time, dyeing is often employed to 
improve furs which are faulty in color. It frequently hap- 
pens, that in a lot of skins there are some which are con- 
siderably off shade, or in which the color is such as to ap- 
preciably reduce their value below the average, the hair 
being usually too light a shade, or of uneven coloring. By 
carefully dyeing these skins of inferior color, they can be 
made to match very closely the best colored skins of the par- 
ticular lot of furs, and consequently increase their value. 
With most of the cheaper kinds of furs, the trouble and cost 
of improvement by dyeing would not be worth while today; 
but with some of the more valuable furs, and especially 
such as are very highly prized, like the Russian sable, or 
marten, or chinchilla, the darkening of light skins by the 
skillful application of fast dyes to the extreme tips of the 
hair, will increase their value sufficiently to warrant the ex- 
pense. This dyeing or ^' blending " as it is called in such 
cases, is done in such a clever and artistic manner that only 
experts can distinguish them from the natural. Dyeing 

91 



FUR DRESSING AND FUR DYEING 

used for such purposes is not objectionable, provided 
the skins are sold as dyed or " blended." 

There are certain kinds of furs, such as the various lambs, 
Persian, Astrachan, Caracul, etc., which are never used in 
their natural color, because it is usually of a rusty brownish- 
black. These are furs possessing valuable qualities other- 
wise, so they are dyed a pretty shade of black, which brings 
out the beauty of the fur to the fullest extent. Sealskins 
are also dyed always. Formerly they were dyed a deep, 
rich dark brown, resembling the finest shades of the natural 
color, but now the seals are dyed black with a brownish 
undertone, a color quite different from the natural. While 
these two instances cannot be said to be cases of dyeing to 
disguise faulty color, they are examples of improvement of 
color by dyeing. 

Closely associated with the use of dyes to increase the 
value of a fur by improving its color, is the dyeing of skins 
of a certain lot of furs to produce a uniform shade, thereby 
facilitating or to a considerable degree eliminating the task 
of matching the skins by the furrier. This is usually done 
only on skins which are quite small, of which a great many 
are needed in the manufacture of fur garments, because 
the matching of several hundred skins would entail too 
much time and labor commensurate wdth the value of the 
fur. The most notable instance of the use of dyes to pro- 
duce a uniform shade on furs is the case of the moleskin. 
Occasionally, furs are dyed after being made into garments, 
by careful application of dyes, in order to obtain certain 
harmonious effects, such as uniformity of stripe, or to pro- 
duce a desired gradation of shade among the different skins 
comprising the garment. 

Not infrequently, the great variety of shades and color 
schemes which Nature provides in the different furs, be- 
comes insufficient to satisfy the desire of the fur-wearing 
public for something new. The whims of fashion always 
require some novel effect, even though it be for only one 

92 



FUR DYEING — INTRODUCTORY 

season. To meet this demand for novelty, fantasy or mode 
shades are produced on suitable furs, — colors which do not 
imitate those of any animal at all, but which, neverthe- 
less, strike the popular fancy. It often happens that such 
a color becomes quite popular, and enjoys a considerable 
vogue, to the great profit of those who introduced the par- 
ticular color effect. The best ones, however, meet with 
only a comparatively short-lived demand, being soon super- 
seded by different color novelties. 

The basis, though, of the greatest proportion of fur dye- 
ing at the present time, is the imitation of the more valu- 
able furs on cheaper or inferior skins. With the gradual 
popularization of furs as wearing apparel since the begin- 
ning of the last century, the demand for furs of all kinds 
has increased enormously. The supply of furs, on the other 
hand, and especially of the rarer kinds, has had difficulty 
in keeping pace with the requirements, and as a result there 
is a shortage. A very effective means of relieving this short- 
age, to a great degree, at any rate, is the dyeing of imita- 
tations of the scarcer furs on cheaper skins. There are 
many animals among the more common, and more easily 
obtainable ones, whose skins are admirably suited as the 
basis of imitations of the more costly furs. Some of the 
furs which are adapted for purposes of dyeing imitations 
are marmot, red fox, rabbit, hare, muskrat, squirrel, opos- 
sum, raccoon, and many others, and the imitations made 
are those of mink, sable, marten, skunk, seal, chinchilla, 
etc., and indeed, there are very few valuable furs, which 
have not been dyed in imitation on cheaper pelts. On ac- 
count of the general mystery which formerly surrounded 
fur dyeing establishments, and which has persisted to this 
day, although to a lesser degree, many peculiar notions 
were held, even by those in the fur trade, concerning the 
production of imitations. The idea that in order to 
"make" a certain fur out of a cheaper skin, it was neces- 
sary to use the blood of the animal imitated, is typical of 

93 



FUR DRESSING AND FUR DYEING 

the conceptions of fur dyeing held not so long ago. To-day, 
while the knowledge generally possessed about this branch 
of the fur industry is meagre and vague, the air of mystery 
and secrecy has become somewhat clarified, and such ideas 
as are current about fur dyeing are more rational than 
formerly. 

The dyeing of imitations is quite an artistic kind of work, 
and indeed fur dyeing ought to be classed among the finest 
of industrial arts. Some of the reproductions achieved by 
dyers on a commercial scale are truly admirable. The 
possibility of imitating the finer furs on cheaper skins 
naturally led to abuse, the dyed furs being passed off fre- 
quently on the unsuspecting and uninformed buyer as the 
genuine original. In fact, this practise became so flagrant 
that in England laws were enacted to remedy the evil. At 
the present time, dyed furs are all sold as such, although 
there always may be some unscrupulous merchants who 
seek to profit by deception. Some of the imitations and the 
names of the furs for which they were sold, are as follows: 

Muskrat, dyed and plucked sold as seal 

Nutria, plucked and dyed sold as seal 

Nutria, plucked and natural sold as beaver 

Rabbit, sheared and dyed sold as seal or electric seal 

Otter, plucked and dyed sold as seal 

IVIarmot, dyed sold as mink or sable 

Fitch, dyed sold as sable 

Rabbit, dyed sold as sable 

Rabbit, dyed and sheared sold as beaver 

IVIuskrat, dyed sold as mink or sable 

Hare, dyed sold as sable, fox, or lynx 

Wallaby, dyed sold as skunk 

White rabbit, natural sold as ermine 

White rabbit, dyed sold as chinchilla 

White hare, dyed or natural sold as foxes, etc. 

Goat, dyed sold as bear, leopard, etc. 

94 



FUR DYEING — INTRODUCTORY 

This list serves to indicate but a few of the great number 
of possibiUties which are available for the fur dyer to pro- 
duce imitations of the better classes of furs. Needless to 
say, these imitations cannot, as a general rule, equal the 
originals, because while the color is one of the most im- 
portant features in judging the fur, the nature of the hair, 
gloss, waviness, thickness, and also the durability are es- 
sential considerations, and it is only in certain instances 
that skins used for imitations approach the originals in 
these respects. However, for the purposes and desires of 
the majority of people who wear furs, the imitations are 
deemed quite satisfactory, and they also have the ad- 
vantage of being cheaper than the natural originals. 

For whichever reason furs are dyed, there is no doubt 
that the art of fur dyeing is one of the most difficult kinds 
of application of dye materials. In the dyeing of the vari- 
ous textiles, either as skein or woven fabric, the material is 
of a uniform nature, and therefore the dye is absorbed 
evenly by the fibres. Moreover, textiles are dyed at, or near 
the boil, the dyestuff being more uniformly and perma- 
nently taken up from solution by the fibre at elevated 
temperatures. 

How different is the case with furs! Far from being 
homogeneous, furs present the greatest possible diversity 
of fibres to be dyed. As already noted elsewhere, fur con- 
sists of two principal parts, the hair and the leather, differing 
widely in their actions toward dyes. As a general rule, the 
leather absorbs dyestuffs much more readily than the 
pelage, and inasmuch as fur dyeing is intended mainly and 
primarily to apply to the hair, there is usually an appreci- 
able loss of dye material due to its being absorbed by the 
leather, and thereby rendered unavailable for dyeing the 
hair. This fact must be taken into account in the dyeing 
of furs, and the methods must be adapted accordingly. 

With reference to the hair itself, not only has each class 
of furs hair of a different kind, but even in the same group 

95 



FUR DRESSING AND FUR DYEING 



there is always a considerable divergence in the properties 
of the hair. The fur-hair, being more or less of a woolly 
nature, takes up the dye with comparative ease, while the 
top-hair is quite resistant to the action of all dye materials. 
As pointed out in the discussion of the nature of fur, on 
different parts of the same pelt the hair varies in its capa- 
city for absorbing coloring matters. The color of the hair, 
also frequently presents a great variety throughout the skin, 
both in fur-hair and top-hair. Yet with all this lack of 
uniformity and homogeneity, the dyed fur must be of an 
even color, closely approaching the natural, gently graded 
and without any harsh or unduly contrasted effects. The 
natural gloss of the hair, one of the most valuable qualities 
of the fur, must be preserved. This is by no means a simple 
matter, for the luster is affected by dyes and chemicals with 
comparative ease, and especially careful treatment is neces- 
sary to prevent any diminution of the gloss. 

When the leather part of the fur is exposed to solutions 
of a temperature exceeding 40°-50° centigrade, it soon 
shrivels up or shrinks, and on drying the pelt, becomes hard 
and brittle, and therefore quite useless. Methods of fur 
dyeing have to take into consideration this fact, and the 
temperature of the dyebath must not be greater than 35°- 
40° centigrade. To be sure, certain dressings make furs 
capable of withstanding much higher temperatures, but 
their applicability is not universal, being suited only 
for a very limited special class of dyestuffs. (V. Fur 
Dressing). The necessity for employing comparatively 
low temperatures, coupled with the great resistance of 
the hair to the absorption of dye, even at much higher 
temperatures, makes fur-dyeing a very difficult opera- 
tion indeed. Another obstacle which must be sur- 
mounted, is the possibility of extraction by the dye 
solution, of those materials, chemical or otherwise, which 
are contained in the leather, and which are the basis of its 
permanence, softness and flexibility. For in the majority 

96 



FUR DYEING — INTRODUCTORY 

of dressing processes, the action of the ingredients is a pre- 
servative one, and when these are wholly or partially re- 
moved from the leather during the dyeing, it becomes, on 
drying, hard and horny, like the original undressed pelt. 
In cases where furs are to be dyed, special dye-resisting 
dressings must be used, or the dyed skins must receive an 
additional dressing before drying. 

Dyeings on furs, to have any value, must possess great 
fastness to light, rubbing and wear, and must not change 
color in time, either when the furs are stored, or when made 
up into garments. The necessity for fur dyeings to have 
these properties, together with the difficulties outlined 
above, has greatly limited the field of available dyeing 
materials, as well as the methods of application. These 
will now be taken up in detail. 



97 



CHAPTER IX 
FUR DYEING 

General Methods 

BEFORE the furs can be dyed, they have to undergo 
certain preparatory processes: first, killing, which 
renders the hair more susceptible to the absorption 
of the dye; and second, mordanting, which consists in treat- 
ing the killed fur with chemicals which help the dye to 
be fixed on the hair. Then the skins are ready to be dyed. 

There are two principal methods by which dyes are ap- 
plied to furs in practise: the brush process, whereby only 
the tips or the upper part of the hair are colored; and the 
dip process, whereby the entire fur, including the leather 
is dyed. All other procedures in fur dyeing are modifica- 
tions or combinations of these two. Killing solutions 
and mordanting solutions are also applied by one of 
these methods, usually the dip process, although very fre- 
quently combinations of the brush and dip methods are 
used. 

Chronologically the brush method of dyeing came first. 
The early masters of the art were extremely fearful about 
employing any means by which there was a possibility of 
the leather being in any way affected. They naturally had 
to devise such methods as would give the desired effect in 
a satisfactory manner, and as would be confined solely to 
the hair part of the fur, leaving the leather untouched. 
By applying the dye or other material to be used, in the 
form of a paste with a brush, the upper portion of the hair 
only was treated. For different kinds of furs different sorts 
of brushes were used, and the depth to which the hair was 

98 



GENERAL METHODS 



colored could be controlled by skillful manipulation of the 
brushes. It was frequently necessary to give a ground color 
to the hair, the lower part being dyed a different shade from 
the tips. This was accomplished by spreading the dye paste 
over the hair with a broad brush, and then beating the 
color in with a specially adapted beating brush. With 
larger furs, two skins were placed hair to hair after the dye 
had been brushed on, and the color forced to the bottom of 
the hair by a workman tramping on the skins. The dye- 
ing of seal was a typical illustration of these procedures. 
First the tips of the hair were dyed. The color was brushed 
on, allowed to dry, then the excess beaten out with rods. 
These operations were repeated until the proper depth of 
shade was obtained, often as many as a dozen or more 
applications of the dye being necessary. Then the base 
color was spread over the hair, and beaten or tramped in 
until the lower parts of the hair were penetrated. This 
process also required drying and beating out of the excess 
dye, as well as numerous applications of the dye to impart 
the desired color to the hair. Prior to the dyeing, the furs 
were killed, by brushing on a paste containing the essential 
ingredients, drying and beating and brushing the fur, just 
the same as in dyeing. It will be readily seen that such 
methods were exceedingly laborious, and in some cases the 
dyeing took many weeks, and even months. 

It was quite a step forward when a certain fur dyer, pos- 
sessing a little more courage, or perhaps, experimenting 
spirit than the others, attempted to dye furs by dipping 
them entirely into a bath containing a solution of the dye 
instead of applying a paste as formerly. The advantages to 
be gained by such a method of dyeing were many. A 
large number of skins could be treated thus at one time, 
and this was a very important consideration in view of the 
great increase in the demand for dyed furs. By allowing 
the furs to remain in the dye solution until the proper shade 
was obtained, the time and labor of applying many coats of 



99 



FUR DRESSING AND FUR DYEING 

dye by brush was considerably reduced, and in addition, 
there was a greater probability of the products coming out 
all alike, uniformly dyed. The results as far as the hair 
was concerned, were indeed highly gratifying, but the con- 
dition of the leather after dyeing was not so encouraging. 
This difficulty has to a considerable degree been overcome, 
although there are frequent instances of the leather being 
affected by the dyeing process even with modern methods. 
However, the remedy in such cases, or rather the preventa- 
tive is the proper dressing of the skins prior to the dyeing. 
The dip method of dyeing has acquired great importance, 
and is being employed in dyeing operations involving the 
handling of millions of skins annually. In certain in- 
stances, nevertheless, the brush method is of prime signifi- 
cance as in the dyeing of seal, and seal imitations on musk- 
rat and coney, enormous quantities of furs being dyed in 
this fashion. In the majority of imitations dyed, both the 
brush and the dip methods must be used. 

Figure 19 illustrates the various types of brushes which 
are used at the present time for the application of the dye 
by the brush method. Each brush has a specific purpose 
and use. The procedure in brush dyeing is somewhat as 
follows. The skins, after being properly treated, that is, 
killed, and mordanted, are placed on a table, or work-bench, 
hair-side up. Then by means of a brush which is adapted 
to the nature and requirements of the particular fur, the 
solution is brushed on in the direction of the fall of the hair, 
occasionally beating gently with the brush so as to cause 
the dye to penetrate to the desired depth. Considerable 
skill and care must be exercised in this operation as it is 
rather easy to force the dye down further than is wanted, 
and in some cases the leather or the roots of the hair may 
be affected. The skin having received its coat of dye, is 
then dried and finished, if no other dyeing processes are to 
be applied. Frequently, with certain types of dyes, several 
applications of color are necessary, and these are brushed 

100 



GENERAL METHODS 



on as the first one, drying each time. Then, on the other 
hand, the skin may receive a dyeing in the bath by dipping, 
and for this also, the fur is first dried after the brush dyeing. 
Quite recently, owing to the great quantities of furs 
which are being dyed as seal imitations, chiefly by the brush 
method, although the dip method is used in conjunction 
with it, machines have been invented to replace the hand 
brush, and the dye is now applied mechanically. Machines 







^¥^^^^|k 



_maoeQfiwwtfi<mnaie>^ 



Fig. 19. Brushes Used in Fur Dyeing By the Brush Method. 



for this purpose are by no means new, there being records 
of inventions almost a score of years past, but they did not 
achieve much success. Brush-dyeing machines, to be effi- 
cient, must be designed to suit the needs of the particular 
type of fur to be dyed, otherwise there will be a great lack 
of uniformity in the dyed skins, a condition which cannot 
occur when the dye is brushed on by hand brushes. Fig- 
ure 20A and B shows diagramatically, machines invented 
within the past few years, which are used to dye mechani- 
cally furs by the brush process. 

101 




Fig. 20. Types of Machines for Dyeing Furs By the Brush Method. 
A. (U. S. Patent 1,225,447.) B. (U. S. Patent 1,343,355.) 

102 



GENERAL METHODS 



For the dipping process, the dye solution is prepared in 
vats, or liquid-tight drums, or in some instances in paddle 
arrangements. The skins are placed in the dye-bath, and 
the dyeing operation proceeds without any difficulty. After 
the proper shade is obtained, the furs are removed, washed 
free of excess dye, dried and finished. The dipping method 




Fig. 21. Drum For Working With Liquids. 
{Turner Tanning Machinery Co., Peabody, Mass.) 

is employed where a single shade is to be dyed on the fur, 
as the production of blacks on lambs. But in most cases, 
the dyeing in the bath is supplemented by the application 
of a coat of dye by the brush to the upper part of the hair, 
the color being usually a darker shade than the ground 
dyeing. Thus, for example, in the dyeing of imitation sable 
on kolinsky or a similar fur, the skins are first dyed the 
relatively light color of the under-hair by the dip process, 
then the dark stripe effect is brushed on. 

103 



FUR DRESSING AND FUR DYEING 

The blending of sables, martens, chinchillas or other rare 
furs, is not done in the same manner as with other furs, 
because each skin requires individual attention and a long 
and careful treatment. The dye solution is applied by- 
means of very fine brushes or sometimes feathers, to the 
extreme tips of the hair, until the proper degree of color 
intensity is obtained. The time, labor, and skill necessary 
for this sort of work are warranted only in the case of the 




Fig. 22. Device For Conveying Skins. 
(^Turner Tanning Machinery Co., Peabody, Mass.) 

highest-priced furs, and the blendings are so excellent as 
to defy detection, except by experts. 

After the furs have gone through all the operations re- 
quired by the processes of killing, mordanting, dyeing and 
washing, they are ready to be dried and finished. The pro- 
cedure is quite similar to that employed in fur dressing. 
Sometimes the leather side of the skins is brushed with 
a strong salt solution before drying, in order to replace some 
of the salt which was extracted during the dyeing processes. 
In other instances, a light coat of some oily substance is 

104 



GENERAL METHODS 



brushed on, to render the leather soft and flexible after 
drying, where there is a possibility of the skins turning out 
otherwise. Great care must be exercised in the handling 
of the dyed skins to avoid the formation of stains or spots 
on the hair, which might ruin the dyeing. As little hand- 
ling of the furs as is feasible will reduce any trouble from 
this source. In conveying the wet skins from one part of 
the plant to another it is desirable to use a device such as 
is shown in Fig. 22. For drying, the same machines as 
described under Fur Dressing can be used, and similar care 
must be taken to avoid overheating or irregularity of dry- 
ing. Drum-cleaning constitutes a very important opera- 
tion in the finishing of the skins, the hair receiving a polish, 
and the full lustre and brilliancy of the dye being thereby 
brought out. Then after caging to remove the sawdust or 
sand, the skins are passed over the staking knife, or are 
treated in a machine suited for the purpose, to stretch them 
and to render them thoroughly soft and flexible. And 
therewith is concluded the work of the fur dyer proper, 
and the skins are ready to return to the furrier, in whose 
hands they undergo the metamorphosis into the fur gar- 
ments to be worn chiefly by the feminine portion of 
humanity. 



105 



CHAPTER X 
FUR DYEING 

" Killing " the Furs 

IF dressed furs are treated with a paste or solution of a 
dye properly prepared, and at the right temperature, 
the hair will show very little tendency to absorb the 
coloring matter. Even after prolonged treatment with the 
dye, only a small amount will be taken up by the hair, 
and in a very irregular fashion. Soft, woolly hair, like that 
of lambs and goats will be colored more easily than that 
of furs with harder hair, and the under-hair of a fur will 
generally have a greater affinity for the dye than the harder 
and stiffer top-hair. Moreover, in some parts of the same 
fur, the hair will absorb more color than in other parts. 
In other words, the hair of furs resists the action of dye 
materials to a greater or less degree, depending upon the 
character of the fur, and also upon the part of the pelt. 
In order to overcome this resistance of the hair, and to 
render it uniformly receptive to the coloring substances, the 
furs are treated with certain chemical agents, the process 
being known technically as " killing." 

The origin of the term is obscure, but it is interesting to 
note that in the fur dyeing countries other than the United 
States and England, the corresponding expression is used: 
in Germany, '' toten," and in France " tuer." The explana- 
tion of the process is as follows: The surface of the hair is 
covered with a fine coat of fatty material which renders the 
hair more or less impervious to dye solutions and solu- 
tions of other substances which may be used for dyeing 
purposes. This fatty coating of the hair cannot be removed 

106 



"KILLING" THE FURS 



by mechanical means, otherwise the hair would have been 
freed of it during the dressing operations. Chemical sol- 
vents must therefore be resorted to, and naturally alkaline 
materials are used, these being usually cheapest and also 
most effective in their dissolving action on fatty substances. 
Alcohol, ether, benzine, and other similar liquids also serve 
as killing agents on furs, since they too, are fat solvents. 
In all these cases, the fatty substance on the hair is dis- 
solved away, and the protective coat which previously ren- 
dered the hair impervious to the dye, is now removed. 
There are certain chemicals however, which normally do 
not dissolve substances of a fatty nature, but are strongly 
oxidizing, such as peroxide of hydrogen, hypochlorites, 
permanganates, perborates, nitric acid, etc., and exert a 
killing action when they are applied to the hair, in that 
the hair is made capable of taking up the dye from its solu- 
tions. In this case the killing can hardly be said to be due 
to a degreasing process. The fact that killing can be 
brought about with other substances than alkalies or fat 
solvents, has led to the belief on the part of some investi- 
gators in this field that killing is more than a degreasing 
operation, although the removal of the fatty material of 
the hair undoubtedly takes place. Some authorities con- 
sider that the killing process changes the pigment of the 
hair, which thereby becomes more receptive to the dye. 
It is quite possible that some such change in the structure 
of the hair fibre does take place, the surface of the hair be- 
coming slightly roughened, and therefore more capable of 
fixing the coloring matter. The question is still an open 
one, and since no conclusive researches have been made 
as yet, it will be assumed that killing is simply a degreasing 
process, inasmuch as the modern practise is based on this 
supposition, and very satisfactory results are obtained. 

An account of the historical development of the killing 
process brings out many interesting and enlightening facts, 
so it will be given here briefly. One of the first substances 



107 



FUR DRESSING AND FUR DYEING 

used for killing, or degreasing the hair of furs, was de- 
composing urine. Urine contains about 2% of urea which 
gradually changes to salts of ammonia, and in the presence 
of the air, largely to ammonium carbonate. This substance 
has a weak alkaline action, but sufficiently effective to be 
used for killing the hair of certain types of furs. Woolly 
furs, such as those derived from the various kinds of sheep 
and goats, were degreased with stale urine, the skins being 
washed in this, and then rinsed in water. The fat was 
emulsified by the ammonium carbonate present, and could 
thus be easily removed. For other furs, a stronger mixture 
was necessary. An example of a killing formula used on 
wolf, skunk and raccoon, which were to be dyed black, is the 
following : 

350 grams beechwood ashes 

200 grams unslaked lime 

150 grams copper vitriol 

100 grams litharge 
60 grams salammoniac 
40 grams crystallized verdigris 

3.5 liters rain water 

Beechwood ashes were a very important constituent of the 
old killing formulas. The reason for that lies in the fact 
that beechwood contains a comparatively high percentage 
of potassium, which occurs in the ashes of the burned wood 
as potassium carbonate, or potash. The ashes alone were 
frequently used, being applied in the form of a paste, which 
in some instances had an advantage over a solution, in that 
the killing could be limited to certain parts of the skin 
where it was more desired than in other parts. By extract- 
ing the wood ashes with hot water, and evaporating the 
clear solution to dryness, potash could be obtained, 
which was considerably stronger than the original ashes. 
Next in importance for the killing was unslaked lime. This 
substance was also often used by itself, being first slaked 

108 



''KILLING" THE FURS 



with water, and using the milk of lime thus formed, after 
cooling. Salammoniac, although a salt, and consequently 
without any killing action, in contact with the beech wood 
ashes or the lime in solution or paste, liberated ammonia 
slowly, and so also acted as a degreasing agent. The other 
chemicals in the formula took no part in the actual killing 
of the hair, but acted either as mordant materials or as 
mineral dyes. The copper salts, in this mixture present in 
two forms, as sulphate in copper vitriol, and as acetate in 
the verdigris, were important constituents of the dye for- 
mula, being essential to the production of the proper shade. 
These substances properly had no place in the killing for- 
mula. The litharge, also was not a killing agent, but in the 
presence of the alkaline materials of the killing mixture, 
it gradually combined with the sulphur contained in the 
hair, forming lead sulphide, and thereby darkening the 
color of the hair. In this case, the metallic compound acted, 
not as a mordant, but as a mineral dye. The mixture was 
applied to the hair by means of a brush, the skins let lie 
for some time, then dried, brushed and beaten. Many 
applications were usually necessary to sufficiently degrease 
the hair. Inasmuch as the killing paste was prepared by 
mixing the constituents together, and then was brushed on 
at the comparatively low temperatures which the proper 
protection of the hair required, it is questionable whether 
some of the metal compounds were even enabled to act as 
described above as mordant or dye. In spite of the trouble 
and considerable time required in working with such a 
killing formula to obtain the hair in the desired condition 
for dyeing, the use of such a mixture nevertheless possessed 
the advantage that the hair was only very slowly and 
gradually acted upon, and so the gloss was preserved. The 
action of strong alkaline substances acting quickly is more 
or less detrimental to keeping the gloss of the hair, while 
the slow action of the weak alkaline paste of the old formu- 
las, and the gradual formation of a protective metal film on 



109 



FUR DRESSING AND FUR DYEING 

the surface of the hair, rendered the hair suitably receptive 
to the dye which was subsequently applied, without in any 
measure affecting the lustre of the hair. 

It would be needless to describe or discuss any more of 
the old killing formulas, for the principle involved was the 
same in all cases, there being usually a slight variation in 
the content of metallic salts, beechwood ashes and unslaked 
lime being constituents of the great majority of the mix- 
tures used. Modern killing processes employ substances 
quite similar to those of the old formulas, the operations, 
however, being much less laborious and less time-consum- 
ing, and the cheap, pure products which chemical science 
has been able to develop being used in place of the crude 
products crudely obtained from natural sources. The chem- 
icals used at the present time for killing furs, are chiefly 
ammonia, soda ash, caustic soda, and caustic lime. The 
choice of the killing agent depends upon the nature of 
the fur, the hair of some furs being sufficiently killed by 
treatment with weak alkalies, while in other furs the hair 
may require stronger treatment. The ability of the hair 
of a particular fur to withstand the action of the different 
alkaline substances must be taken into consideration, there 
being a great divergence in this regard among the different 
classes of furs. Raccoon, for example, is not appreciably 
affected by a solution of caustic soda of 5 degrees Beaume, 
while some wolf hair cannot withstand the action of a solu- 
tion of soda ash of less than 1 degree Beaume. Frequently 
much stronger alkalies are necessary to kill the top- 
hair than the under-hair, so this accomplished by treat- 
ing the skins in a solution which is suited to kill the 
under-hair, and subsequently the top-hair is treated with 
a stronger solution, this being applied by the brush 
method. 

Uniformity of action of the killing material on all parts 
of the skin, and on all the skins of a given lot, is absolutely 
essential to obtaining satisfactory results in dyeing. And 

110 



"KILLING" THE FURS 



it is by no means a simple matter to get such uniformity, 
considering the numerous factors that must be taken into 
account. Any operation involving the immersion of the 
skins in solutions or even in water alone, has an effect on 
the leather side of the skin, inasmuch as some of the tan- 
ning materials may be extracted. The application of some 
substance of a fatty nature to a great degree prevents this, 
and the skin can be killed, mordanted and dyed, and then 
come out soft and flexible. But the great majority of 
substances of a fatty nature are affected by alkalies, and so 
when the skins are being killed, the action of the alkaline 
materials would be upon the fat contained in the leather 
as well as that upon the hair. As a result the hair may 
not be sufficiently killed, and so give uneven dyeings sub- 
sequently. Either a certain excess of the killing chemical 
must be used, and it would be very difficult to ascertain what 
quantity would suffice, or the killing action must be 
prolonged; but best of all, in oiling the skins, an inert 
mineral oil should be used, since it is wholly unaffected by 
alkalies. 

Skins may be killed by the brush process or the dip proc- 
ess, or by both. For brush killing, the stronger alkalies 
like lime and caustic soda are used, the solution being ap- 
plied to the top-hair with a suitable brush, and the skins 
allowed to remain hair to hair for the necessary length of 
time, after which they are treated further as skins killed 
by the dip process. By this latter process, the furs are 
immersed in a solution of the desired killing agent in a vat, 
or drum, or other appropriate device which will permit of 
uniform action of the alkali on the hair of all the skins. 
After remaining in the solution the required length of time, 
the skins are drained, and rinsed in fresh water, and then 
entered into a weak solution of an acid in order to neutralize 
any remaining alkali, it being easier to wash out acid than 
alkali. The furs are then washed thoroughly in clear water, 
preferably running water, to remove the last traces of acid. 

Ill 



FUR DRESSING AND FUR DYEING 

The skins are then drained and hydro-extracted, or pressed, 
and are then ready for the subsequent operations of mor- 
danting and dyeing. 



Killing with Soda 

Soda is sodium carbonate, which is produced commer- 
cially in a very pure state in several different forms, the 
chief being sal soda, which is crystallized sodium carbonate, 
containing about 37% of actual soda; and soda ash, or 
calcined soda, which is anhydrous sodium carbonate. The 
latter is the variety most commonly used. 

10 grams soda ash are dissolved in 
1 nter of water at 25^''-30° C. 

The skins are immersed for 2-3 hours, after which they are 
rinsed and treated with 

10 grams acetic acid dissolved in 
1 liter of water. 

The skins are again thoroughly washed, and then hydro- 
extracted. 

Killing with Lime 

Lime, calcium oxide, forms a white, amorphous, porous 
substance, which readily takes up water, giving calcium 
hydroxide, or slaked lime. Only the best grades of lime 
should be used, as it is very frequently contaminated with 
calcium carbonate and other inert materials. 

10 grams of lime are dissolved in 
1 liter of water. 

The skins are entered, and allowed to remain for a period 
of time which varies according to the nature of the fur. 
During the killing, the solution must be agitated, in order 
to evenly distribute the milk of lime, which has a tendency 

112 



"KILLING" THE FURS 



to settle out. After rinsing, the skins are " soured," by- 
treating with weak acetic acid solution, then thoroughly 
washed, and drained. 

Killing with Caustic Soda 

Caustic soda is used only on furs the hair of which is 
very hard and resistant to killing. LTsually it is applied 
by the brush process, but in some instances, the dip method 
must be used. In order to reduce as far as possible, the 
action of the caustic soda on the leather, the weakest per- 
missible solutions are used, increasing the time of treat- 
ment, if necessary. Caustic soda is a white, crystalline 
substance, occurring in commerce in lumps, but more con- 
veniently in a solution of 40 degrees Beaume, containing 
35% of caustic soda. Various quantities, ranging from 4 
to 25 grams of this solution per liter of water are taken, 
according to the character of the fur, and the skins treated 
for 2-3 hours, although weaker solutions may be used, and 
increasing the duration of the killing. By keeping the 
solution in motion, by means of a stirrer or any other 
method of agitation, the best results are obtained. After 
the skins are sufficiently killed, they are soured, and washed 
as by the other killing methods. 

Where the nature of the hair of the fur is such that the 
top-hair and the under-hair require different killing treat- 
ments, the skins are first killed by the dip process, with 
an alkali suited to kill the under-hair, then a brush killing 
with a stronger alkali is applied to the top-hair. The 
subsequent treatments are the same as for usual dip-killing 
methods. 



113 



CHAPTER XI 
FUR DYEING 

Mordants 

THE hair of furs has the peculiar quality of fixing 
the oxides or hydroxides of certain metals from 
dilute solutions of their salts. Advantage is taken 
of this property to mordant the furs, that is, to cause a cer- 
tain amount of the metallic oxide or hydroxide to be perma- 
nently absorbed by the fibres. The term mordant comes 
from the French word " mordre," meaning to bite, it being 
formerly considered that the purpose of a mordant was to at- 
tack the surface of the hair in such a way as to permit the 
dye to be more easily absorbed. In fact, killing mixtures, 
which were intended for this same object, used to contain 
the various chemicals which have a mordanting action, 
in addition to the alkaline constituents. The mordants 
were not applied as such, but always as killing materials. 
It was later realized, however, that the mordant was instru- 
mental in the production of the color itself. 

Mordanting may be considered as having a two-fold 
object: first, to help fix the dye on the fibre in a more 
permanent fashion, thus rendering the dyeings faster; and 
secondly, to help obtain certain shades of color, as the 
various mordants produce different shades with any given 
dye. Some classes of dyes can be applied to furs without 
the use of mordants, but other types are taken up only in 
a very loose manner, being easily washed out from the 
hair with water, and it is only when such dyes are brought 
on to the hair in the form of a metallic compound, pro- 

114 



MORDANTS 



ducing what is known as a '' lake," that really fast dyeings 
are obtained with them. The substances which are used for 
mordanting the hair are certain metallic compounds, but 
not all metallic salts which are used in dyeing are mordants. 
Sometimes such a compound is employed to develop the 
color of the dyeing by after-treatment, as in the case of 
after-chroming, the action of the metallic salt being directed 
only to the dye, and is not fixed by the fibre as a mordant 
must be. In order for a metallic compound to act as a 
true mordant, it must be fixed by the hair, and it must 
combine with the dye, thus forming a sort of connecting 
link between the dye and the hair. It is not absolutely 
essential that the mordant be applied first, although this 
is the customary and commonest practise. There are three 
ways by which the mordants. can be fixed on the fur hair: 
First, by the absorption of the metallic oxide or hydroxide 
from a solution of the mordant prior to the dyeing; second, 
the mordant may be fixed on the fibre at the same time 
as the dye; and third, the mordant may be applied after 
the fur has been treated with the dye. The last two meth- 
ods will be discussed in connection with the dyes, as they 
are special cases. 

The salts of metals which are comparatively easily dis- 
sociated in water, with the formation of insoluble oxides 
or hydroxides, are most applicable as mordants for furs, 
and among them are compounds of aluminum, iron, chro- 
mium, copper and tin. The constituents of the hair seem 
to bring about the dissociation of the metallic salt, and 
the oxide or hydroxide as the case may be, is absorbed and 
firmly fixed by the hair. Just what the manner and nature 
of this fixation are, is still uncertain. It is supposed that 
chemical combination takes place between the hair and 
the metal. The course of this process may, as far as is 
known, be described as follows, taking, for example, the 
case of chromium sulphate: In dilute solution, this com- 
pound gradually dissociates first into its basic salts, and 



115 



FUR DRESSING AND FUR DYEING 

finally into the hydroxide, the breaking up of the neutral 
salt being induced by the presence of the fur-hair, 

Cro(S04)3 + 2HoO = Cro (804)2 (OH). + H2SO4 

chromium water first basic sulphuric 

sulphate " chrome salt acid 

Cr2(S04)2(OH)2 + 2H20 = Cr2(S04)(OH)4 + H2SO4 

second basic 
chrome salt 

Cr2(S04)(OH)4 + 2H2O = Cr2(OH)6 + H2SO4 

chromium 
hydroxide 

These reactions take place within the fibre, after the hair 
has been impregnated with the solution of the neutral salt, 
and when the compound has been rendered completely 
basic, in other words has reached the form of the hydroxide, 
it is supposed to combine with the acid groups contained in 
the hair substance, forming thus some complex, insoluble 
organic compound of the metal within the hair. Accord- 
ing to some authorities the mordant is supposed to be 
present in the hair simply as the hydroxide, being tena- 
ciously held by some physical means. The facts seem to 
indicate, however, that the metal is actually combined in 
some chemical way with the hair. For, if the mordant were 
present as hydroxide, then on white hair it would show 
the color of the hyth'oxide, which it does not. The same 
facts obtain with regard to other metals. 

In order for the hair to be properly mordanted, it is nec- 
essary that the metallic compound which is taken up by 
the hair be held in such a manner that the mordant cannot 
be removed by water or even dilute acids or alkalies. Salts 
which dissociate too readily produce mordants which are 
only superficially precipitated on the hair and subsequently 
come off. Usually some substance is added to the solution 
of the salt to cause slower and more even dissociation of 
the salt, so that the hair substance can be quite saturated 
with the metallic compound before any insoluble precipi- 

116 



MORDANTS 



tate is formed. Dilute sulphuric acid, organic acids like 
acetic and lactic, and cream of tartar are used to facilitate 
the uniform absorption of the mordant salt by the hair. 

When the skins are mordanted before dyeing, they are 
immersed for 6 to 24 hours in a solution containing 1 to 
20 grams of the metallic salts per liter of water, together 
with the corresponding quantity of the assistant chemical. 
The skins should be so entered into the mordant solution 
that the hair is uniformly in contact with the solution, and 
all the skins so that they are acted upon alike. Machinery 
such as is used for killing is suitable for mordanting also. 
The duration of the mordanting, and the concentration of 
the solutions are varied according to the depth of shade 
required, and also according to the nature of the dye to be 
employed. By suitably combining several mordants a con- 
siderable range of colors can be obtained with a single dye. 

The various chemicals used as mordants are essentially 
the same no matter for which class of dyes they are used, 
there being only slight differences in the concentrations of 
the solutions, the manner of application of the mordants 
being practically the same. It is interesting to note that 
with the exception of chromium compounds, which are of 
comparatively recent adoption as mordants, all the chemi- 
cals now used for mordants were employed by the earliest 
masters of the art of fur dyeing. While some of the formu- 
las used by those dyers display a lack of appreciation of 
the true action and function of the mordanting chemicals, 
yet it is quite remarkable that they chose, in spite of their 
limited knowledge of chemical processes and phenomena, 
just those materials which do act as mordants if prop- 
erly applied. The most important metallic compounds for 
mordanting furs at the present time are salts of aluminum, 
iron (ferrous), copper, tin and chromium (as well as chro- 
mates and bichromates). The compounds of the metals 
with organic acids such as acetic acid are preferable, being 
more easily dissociated, and also leaving in solution an acid 



117 



FUR DRESSING AND FUR DYEING 

which is less injurious to the fur than a mineral acid. How- 
ever, sulphates and other salts of the metals are also used ex- 
tensively, inasmuch as they are cheaper than the organic 
salts. 

Aluminum Mordants 

Chief among the aluminum mordants are the various 
kinds of alum, which is a double sulphate of aluminum and 
an alkali such as sodium, potassium or ammonium. All 
these salts except that of sodium, form large, colorless, 
octahedral crystals, and are soluble in about 10 parts of 
cold water, and ^ part of hot water. Sodium alum is even 
more easily soluble, but on account of the difficulty of 
obtaining it in crystalline form, it is little used. The com- 
mon commercial alum is the potassium aluminum sulphate. 

Recently, aluminum sulphate has to a large extent re- 
placed alum for mordanting purposes, because it can be 
obtained very cheaply in pure form, and it contains a 
greater amount of active aluminum compound than does 
alum. Only the iron-free salt, however, may be used for 
the needs of fur dyeing. 

Aluminum acetate also finds extensive application as a 
mordant in fur dyeing, and while somewhat more expensive 
than the alum or aluminum sulphate, it has the advantage 
over these compounds of being combined with an organic 
acid, which is preferable when the action on the hair and 
leather is considered. Aluminum acetate can be obtained 
in the market in the form of a solution of 10 degrees 
Beaume, but can also be prepared very easily as follows : 

665 grams pure aluminum sulphate, or 
948 grams potassium alum, are dissolved in 

1 liter of hot water. 
1137 grams of lead acetate (sugar of lead) are also 
dissolved in 
1 liter of hot water. 



118 



MORDANTS 



The two solutions are mixed, and thoroughly stirred. A 
heavy white precipitate forms, which is filtered off, and dis- 
carded after the solution has cooled. The aluminum ace- 
tate is contained in the filtrate, and the solution is brought 
to a density of 10 degrees Beaume by the addition of water, 
if necessary, and is preserved for use in this form. 

Iron Mordants 

Ferrous sulphate, iron vitriol, or copperas, as it is com- 
monly known, forms pale green crystals, which on exposure 
to air lose water, and crumble down to a white powder. It 
is very soluble in both cold and hot water, but the solutions 
oxidize very rapidly, turning yellowish, and should there- 
fore be used immediately. Care must be taken that a good 
quality of iron vitriol be used for the mordant, otherwise 
very unsatisfactory results will be obtained. 

Ferrous acetate is prepared in a manner similar to the 
aluminum acetate, and is occasionally employed instead of 
the ferrous sulphate. Inasmuch, however, as the solution 
of ferrous acetate is very easily oxidizable when exposed to 
the air, a more stable form is used, and this comes on the 
market as iron pyrolignite or iron liquor. This can be 
prepared by dissolving iron in crude acetic or pyroligneous 
acid, or by treating a solution of iron sulphate with calcium 
pyrolignite. Iron liquor is really a solution of ferrous ace- 
tate that contains certain organic impurities w^hich prevent, 
or rather, considerably retard the oxidation of the iron salt, 
but which in no way interfere with its mordanting proper- 
ties. The commercial product can be had in various con- 
centrations, but 10 degrees Beaume is the most usual and 
most convenient. 

Copper Mordants 

The most important copper salts used in fur dyeing 
processes are copper sulphate, or blue vitriol, occurring in 

119 



FUR DRESSING AND FUR DYEING 

large blue crystals, very soluble in cold and in hot water; 
and copper acetate, which is formed by treating a solution 
of copper sulphate with a solution of the requisite quantity 
of lead acetate. Copper acetate can also be obtained in 
the form of blue-green crystals, very soluble in water, the 
solution becoming turbid on prolonged heating, due to the 
formation of a greenish basic copper acetate. This insol- 
uble compound is known commonly as verdigris, although 
it is not usually produced in the manner mentioned. Nu- 
merous fur dyeing formulas contain verdigris, but inasmuch 
as the basic copper acetate is insoluble and thus incapable 
of reacting with any of the substances used in dyeing, it is 
assumed that the soluble normal copper acetate was meant, 
for this compound is also sometimes called verdigris. 

In addition, there must be mentioned here a compound 
which formerly found extensive use in fur dyeing. This 
is a double salt of copper and iron, analogous to alum, fer- 
rous copper sulphate, known as blue salt. It is very seldom 
used at the present time, being more effectively replaced 
by other substances. 

Chromium Mordants 

The typical chromium mordant is chrome alum, which is 
a potassium or ammonium chromium sulphate, constituted 
just like the aluminum alums, and forming crystals like 
these. More frequently used, nevertheless, than the chrome 
alum, is chromium acetate, which is prepared from it, 
either by treating a solution of the chrome alum with a 
solution of lead acetate, or in the following manner : 

50 grams of chrome alum are dissolved in 
500 cubic centimeters of boiling water. To this 
is added 
15 grams of 20% ammonia, diluted with 15 
grams of water. 

120 



MORDANTS 



The precipitate which forms is filtered off, and preserved, 
the filtrate being discarded. After thoroughly washing 
the residue on the filter it is dissolved in dilute acetic acid, 
heating if necessary, to effect solution. 

Other chromium compounds of an entirely different type 
are also used in fur dyeing, these being chromates and 
bichromates, the latter finding greater application than the 
former. Sodium bichromate is the salt most usually em- 
ployed. This forms orange-red crystals which are very 
soluble in water, and in addition to its use as a mordant it 
also serves as an oxidizing agent for developing or fixing 
certain dyes on furs. 



Tin Mordants 

Compounds of tin find only limited application in fur- 
dyeing, the only one of importance being tin salts, stannous 
chloride, which occurs in the form of white, hygroscopic 
crystals, which must be preserved in closed vessels. It is 
very soluble, but in dilute solutions it readily forms a basic 
salt, so stannous chloride is usually used in very concen- 
trated solutions. 

Alkaline Mordants 

After the furs have been treated with the solution of 
some alkali for the purpose of killing the hair, they are 
always passed through a slightly acidulated bath to re- 
move any alkali which may still be adhering. This opera- 
tion must always be gone through before the skins can 
be mordanted or dyed, for if it were neglected, very uneven 
and uncertain results would be obtained. This process, 
however, entails the expenditure of no small amount of 
time, labor and chemicals when large lots of skins are being 
handled. In order to eliminate this extra step of " souring " 
between killing and mordanting or dyeing, it has been pro- 

121 



FUR DRESSING AND FUR DYEING 

posed to use alkaline mordants which combine the killing 
and mordanting functions, and accomplish these two proc- 
esses at the same time. The advantages of employing 
such mordants are easily apparent. Cumbersome manip- 
ulation and handling of the skins, with the attendant con- 
sumption of much time and labor are reduced to a mini- 
mum, and besides there is no needless waste of chemicals as 
is the case in the ordinary methods of killing the furs. 

The principle of alkaline mordants is not a strictly new 
one. If it be remembered that the old killing formulas used 
by the fur dyers of an earlier age, contained metallic salts 
with mordanting properties in addition to the alkaline sub- 
stances, which alone were effective as killing agents, it 
would seem that the suggested alkaline mordants were 
merely a revival in modified form of the old processes. This 
is undoubtedly true in a large measure, for the killing mix- 
tures which the old masters used certainly embodied the 
fundamental principle of simultaneous killing and mor- 
danting, although it was not recognized at that time. 

Modern alkaline mordants have therefore been devised 
which can be employed for killing and mordanting furs at 
the same time. They are prepared as follows : 

Alkaline Aluminum Mordant 

250 grams of potassium alum are dissolved in 

1 liter of boiling water. To this solution 

is added 

300 grams of soda ash, previously dissolved in 

750 c.c. of water, and the resulting precipitate is 

filtered off, washed and pressed, and then dissolved in a 

"solution of 65 grams of caustic soda in 1 liter of water. 



122 



MORDANTS 



Alkaline Chromium Mordant 

250 c.c. of chrome acetate mordant of 20 de- 
grees Beaume 

320 c.c. of caustic soda solution of 38 degrees 
Beaume (32.5%) 
10 c.c. of glycerine 30 degrees Beaume (95%) 

The solution of these substances is brought up to a volume 
of 1 liter by the addition of 420 c.c. of water. 

Alkaline Iron Mordant 

138 grams ferrous sulphate are dissolved in 
362 c.c. of warm water. Cool and add 
25 c.c. of glycerine. Then slowly and carefully 
add 
25.5 c.c. of concentrated ammonia, taking care 
that no precipitate forms. 

While these alkaline mordants seem to have much in 
their favor, there are certain possible objectionable features 
which must be considered. The solutions of the mordants 
are generally very alkaline, and not every fur can withstand 
more than a limited quantity of alkaline substance for 
longer than a comparatively short time. Suitable mordant- 
ing usually requires a longer time than killing does, so 
with the use of the alkaline mordant, if the skins remain 
in the solution until sufficiently killed, they may be in- 
sufficiently mordanted, while if the furs are treated long 
enough to be properly mordanted, the hair may have been 
over-killed. However, the idea of the alkaline mordant is 
a good one, and it is only a matter of time and patient, 
scientific experimentation when the difficulties of the 
method will be eliminated, and a much-desired process will 
become a practical realization. 

123 



FUR DRESSING AND FUR DYEING 

The general methods for applying the various mordants 
of all sorts follow closely the procedure adopted for the 
killing formulas, and similar precautions must be observed, 
in order to obtain consistently uniform results. With the 
exercise of care, there is little reason for the mordanting 
operations to go wrong. 

After proper treatment of the skins in the mordants, 
they are removed and drained off, then rinsed lightly in 
running water to remove the excess of mordant liquor, 
after which they can be directly entered into the dye bath. 
If it is not feasible to dye the mordanted skins at once, 
as is often the case, the skins are kept moist, and under 
no circumstances allowed to dry. 



124 



CHAPTER XII 
FUR DYEING 

Mineral Colors Used on Furs 

BEFORE the introduction of the fur dyes now used, 
certain inorganic chemical substances were em- 
ployed in addition to the vegetable dyes, for the 
production of colors on furs. Even to this day such mate- 
rials are used to obtain certain effects in special instances. 
The idea of employing mineral chemicals undoubtedly ori- 
ginated in the textile-dyeing industry, which at one time 
was dependent to an appreciable extent on mineral sub- 
stances for the production of certain fast shades. Com- 
pounds of iron, lead, manganese, also of copper, cobalt and 
nickel were all used for dyeing, either singly or in various 
combinations. In the application on furs^, the brush 
method was the only one practicable, as the skins 
would have been ruined by dipping them into solutions of 
these chemicals in the concentrations necessary for dyeing. 
The dyeing of furs with mineral colors involves the pre- 
cipitation on the fibre in a more or less permanent form 
of the sulphide, oxide or other insoluble compound of a 
metal, and can be brought about in several ways. By 
what is known as double decomposition, that is, by the use 
of two solutions successively applied, the ingredient of one 
causing a precipitate to form when in contact with the 
constituent of the second, the color is produced on the hair. 
Another method is to use solutions of chemicals which 
decompose on contact with the hair, forming an insoluble 
compound. In the first method the hair is alternately 
treated with the two solutions of the requisite chemicals, 

125 



FUR DRESSING AND FUR DYEING 

drying between each brushing, the process being repeated 
until the desired shade is obtained. The second method 
merely requires the solution of the chemical to be applied 
to the hair, which is then dried, the color forming by itself. 
One of the most important of the mineral dyes, and 
which is occasionally used to this day, is lead sulphide, 
formed by the double decomposition method by precipita- 
ting a soluble lead salt with ammonium sulphide, or any 
other alkaline sulphide. By simply brushing an aqueous 
solution of lead acetate, also known as sugar of lead, on a 
white fur such as white hare or rabbit, a light, brownish 
coloration is obtained due to the combination of the lead 
with the sulphur of the hair. If the lead solution is care- 
fully applied several times on this type of fur, until a 
sufficiently dark color is produced, it is possible to get a 
fairly good imitation of the stone marten. The brown color 
is very fast, being actually formed within the hair. In 
most cases, however, for dyeing lead sulphide shades 
it is necessary to use the two solutions. Thus the pale 
greyish or slightly brownish-grey shades of the lynx can 
be reproduced on white rabbit or hare by this process. A 
solution containing 60 grams of lead acetate per liter of 
water is brushed on to the hair of the fur which has pre- 
viously been killed in the usual manner, and the hair is 
then dried. A solution of 50 grams of ammonium sulphide 
per liter of water is next brushed on, and the fur again 
dried. Care must be exercised in handling the ammonium 
sulphide as it is a very malodorous liquid, the fumes of 
which are poisonous when inhaled. The alternate brush- 
ings are repeated until the desired depth of shade is ob- 
tained. A very dark brown, approaching a black can be 
obtained in this way. This color can be used for the 
production of certain attractive effects. By brushing over 
the tips of the hair, which has previously been dyed a 
dark brown by means of the lead sulphide color, with a 
dilute solution of hydrochloric acid, or with peroxide of 

126 



MINERAL COLORS USED ON FURS 

hydrogen, the hair will become white in the parts so treated, 
due to the formation of lead chloride or lead sulphate, 
respectively. Thus white tipped furs can be obtained, but 
the process is applicable only when the furs have been 
dyed by the lead sulphide method. 

Potassium permanganate is occasionally used to produce 
dyeings of a brown shade on furs. Considerable care has 
to be taken in applying this substance, as it is possible to 
affect the hair. The strength of the solution must be va- 
ried according as the hair to be dyed is weak or strong. 
A cold solution of 10 to 20 grams of potassium permanga- 
nate per liter of water is brushed on to the hair, which is 
then dried. A brown precipitate of manganese is formed 
on the hair after a short time, and the process is repeated 
until the required shade is obtained. For furs with harder 
hair, stronger solutions can be used. The dyeing is very 
fast, but it is seldom used, cheaper and better shades being 
obtained in other ways. Spotted white effects can be pro- 
duced on the brown dyeing with permanganate of potash 
by applying a solution of sodium bisulphite, the brown 
color being dissolved by this chemical. 

The compounds of other metals, such as iron, copper, 
cobalt and nickel are not used in practise as the dyeings 
are not fast, and can be better produced in other ways. 



127 



CHAPTER XIII 
FUR DYEING 

Vegetable Dyes 

WITH the exception of the few shades which could 
be produced solely by means of coloring matters 
of a chemical character, all dyeings on furs up to 
about thirty years ago were made with dye substances 
obtained from the vegetable kingdom, either alone, or in 
conjunction with the aforementioned mineral colors. The 
colors of vegetable origin used in comparatively recent 
times were mainly extracts of the wood of certain trees; so 
the name " wood dyes " has come to be applied generally 
to the dyes of this class. The use of the vegetable or nat- 
ural dyes on furs dates back to quite ancient times, as 
frequent allusions and descriptions in Biblical and other 
contemporaneous literature testify. There are numerous 
pictures on monuments and tablets illustrating the dyeing 
of furs among the ancient Egyptians, the evidence indicat- 
ing that the juice of certain berries, and extracts of certain 
leaves, were used for the purpose. At a later period, in the 
Roman era, henna, which was used over two thousand years 
ago as to-day for the beautification of the hair of women, was 
also used to color fur skins. The instances cited here are 
merely of scientific and historical interest, and are not of 
practical importance as far as fur dyeing methods are 
concerned. 

It was not until many centuries later that the dyeing of 
furs took on the aspects of a commercial art, and the sub- 
stances then employed were chiefly tannin-containing ma- 
terials such as gall-nuts and sumach, which in conduction 

128 



VEGETABLE DYES 



with certain metallic salts, particularly those of iron, were 
capable of producing dark shades. The use of iron com- 
pounds to form dark grey or black colors on leather tanned 
by means of the tannins, had been common for a long 
time, and it was natural that fur dyers should try to pro- 
duce such shades on furs in a similar fashion. The use 
of the iron-tannin compound as a dye proved to be very 
effective, and to this day the production of blacks by means 
of the vegetable coloring matters has as a basis an iron- 
tannate. A formula in common use in the latter seven- 
teenth and the eighteenth centuries for producing black 
shades on furs, is the following: 



Lime water 


1117 parts 


Gall-nuts 


1500 ' 




Litharge 


500 ' 




Salammoniac 


65 ' 




Alum 


128 ' 




Verdigris 


64 ' 




Antimony 


64 ' 




Minium 


32 ' 




Iron filings 


128 ' 




Green copperas 


384 ' 





All these substances except the gall-nuts, the copperas and 
half the lime water were boiled up in a cauldron; then the 
gall-nuts and the copperas were placed in a bucket and the 
contents of the cauldron poured in, and the rest of the lime 
water added. The mixture was stirred up, allowed to settle 
for an hour, and when cool, was ready to be applied by 
the brush method. For dyeing by the dip process, a similar 
mixture was used, only considerably diluted with water. 
A study of the formula discloses the fact that in it are 
combined killing and mordanting substances as well as 
dyeing materials. The lime water, in conjunction with the 
salammoniac serves as a killing agent, the verdigris, cop- 

129 



FUR DRESSING AND FUR DYEING 

peras and alum are mordants, while the litharge and the 
minium, both compounds of lead, could possibly act as 
mineral dyes, and the iron filings and the antimony took 
virtually no part at all in the dyeing, except, perhaps to 
act in a mechanical way. 

The formulas for other shades were made up along sim- 
ilar lines, the chief constituent of vegetable nature being 
either gall-nuts, sumach, or both. A mixture for a chestnut 
brown, for example, contained gall-nuts, sumach, and the 
various other mineral constituents as in the black dye, 
litharge, alum, copperas, verdigris, salammoniac, antimony, 
and in addition, red lead and white lead. It is evident in 
both these instances that the shade obtained was as much 
the result of mineral dyeing as of vegetable dyeing. 

The discovery of America introduced into Europe many 
new dye substances, chiefly wood extracts such as logwood 
and Brazilwood, but it was not until the nineteenth cen- 
tury that these materials found their way into the dye 
formulas of the fur dyer. Most of the processes used in 
the dyeing of furs were adaptations of methods employed 
in silk dyeing, the silk fibre being considered as most nearly 
approaching fur-hair in nature and characteristics. By 
devious and circuitous paths the formulas of the silk dyers 
reached the fur people, and so, in the middle of the nine- 
teenth century, dye mixtures containing the various dye- 
woods as well as the tannin-containing substances were in 
general use for the dyeing of furs. The following is 
a typical recipe of that time for the production of black 
on furs like wolf, skunk, raccoon, etc. : 



Roasted gall-nuts 


1000 parts 


Sumach 


200 " 


Iron mordant 


200 " 


Copper vitriol 


100 " 


Litharge 


80 " 


Alum 


60 " 



130 



VEGETABLE DYES 



Salammoniac 50 " 

Crystallized verdigris 40 " 

French logwood extract 30 " 

Rain water 7000 " 

The mixture was boiled up, and after cooling was ready 
for application by the brush method, the skins being first 
killed by a killing mixture also applied by the brush. The 
dye substances in this case are the gall-nuts, sumach and 
the logwood extract, with the iron mordant, copper vitriol, 
and alum as mordants. For brown shades a similar formula 
was used containing Pernambuco wood extract, logwood 
extract, quercitron bark, gall-nuts and dragonblood, together 
with iron, copper and alum mordants. 

Formulas such as the above were mainly empirical, that 
is, they were compounded as a result of trial of various 
combinations of the constituents, without considering the 
nature and quantitative character of the reactions, as long 
as the desired shades could be obtained. Such dye mixtures 
were frequently found to yield results varying from those 
expected or originally obtained, because the effectiveness 
of the formulas depended upon the exact duplication in 
every detail, of conditions which had given satisfactory 
results previously, and it was not always possible to attain 
such an accurate reproduction of circumstances, especially 
when the fur dyers were quite ignorant of the scientific 
relationships of the materials used. So when more light 
had been shed on the nature and chemical characteristics 
of the vegetable dye substances, formulas like those des- 
cribed were no longer employed, although the essential 
ingredients were the same in the new processes. Unneces- 
sary constituents were eliminated, and proper ones sub- 
stituted where it was required, and the quantities of the 
materials used were made to conform to the chemical laws 
governing the reactions. Since these new formulas were 
based on a rational understanding of the constituents and 

131 



FUR DRESSING AND FUR DYEING 

their reactions, it is desirable to study the latter briefly, 
before further discussing the formulas themselves. 

The substances of vegetable origin used in modern fur 
dyeing may be grouped into two classes, one, the tannin- 
containing materials, and the other, the dyewoods proper. 
The most important of the tannins are gall-nuts, sumach 
and chestnut extract. Cutch, which also comes under this 
class, is more frequently used for the production of brown 
shades, so it is grouped with the dyewoods. Among the 
latter are logwood, fustic, Brazilwood, quercitron, turmeric, 
and several others of less significance. 

1. Tannin Materials 

First and foremost under this heading are the nutgalls. 
These are ball-shaped excrescences produced on certain 
plants by the punctures of insects in depositing their eggs. 
There are two chief varieties, the European, and the 
Chinese. The European galls are formed by the female 
gall-wasp which drops an egg in the rind of young branches 
of certain oaks. A swelling (the nutgall) is produced, in 
which the young insect develops, and from which it finally 
escapes by piercing a hole through the shell. Those galls 
which are not pierced have a fresh bluish or green color, 
are heavy and contain most tannic acid. After the insect 
has gone out, the galls are of a lighter, yellowish color, 
and also of inferior quality. The best oak-galls are the 
Aleppo, and the Turkish or Levant galls, containing 55- 
60% of tannic acid, and about 4% of gallic acid. The 
Chinese galls are produced by the puncture of a plant- 
louse on the leaves and leaf-stalks of a species of sumach, 
and not on oaks. The galls are very light, and very rich 
in tannic acid, containing often as much as 80%. For 
dyeing purposes, nutgalls are usually ground to a powder, 
and in some instances they are even roasted first and then 
ground. 

132 



VEGETABLE DYES 



Sumach consists of the leaves and sometimes of the 
small twigs and stems of a species of sumach plant known 
as the Rhus coriaria. The Sicilian variety is the finest 
commercial quality, with the Virginian ranking next. It 
is sold as a powder, but also in the form of the whole or 
crushed leaves. The best sumach contains 15-25% of 
tannin. Extracts are also manufactured, a liquid extract 
of 52 degrees Twaddell, which forms a dark brown, thick 
paste ; and a solid extract, formed by evaporating the liquid 
extract to dryness. 

Chestnut extract is prepared from the wood of the chest- 
nut oak, which contains 8-10% of tannin. The solid ex- 
tract has a bright, black color, while the liquid extract is 
a dark brown paste with a smell like that of burnt sugar. 

The tannins all give greyish to black shades with iron 
salts, and it is this fact which renders them important for 
fur dyeing. 

2. Wood dyes 

One of the most important of all the natural dye sub- 
stances, especially for the production of blacks, is logwood. 
The color is really a red, but with the common mordants 
it forms blue, violet or black shades. Logwood, or cam- 
peachy wood, as it is sometimes called, is the product of a 
large tree growing in the West Indies, and Central and South 
America. When freshly cut, the wood is practically with- 
out color, but when exposed to the air it soon becomes a 
dark reddish-brown on the surface. The coloring principle 
of logwood is called hematoxylin, which is a colorless sub- 
stance when pure, and is of itself incapable of dyeing; but 
when it is exposed to the air, especially when moist and in 
the presence of some alkaline substance, it is converted into 
hematein, which is the real coloring matter of logwood. To 
prepare the wood for use, the logs are chipped or rasped, 
the chips being heaped up and moistened with, water. Fer- 
mentation occurs, and the heaps are frequently turned to 
allow free access of air to the wood, and to prevent over- 



133 



FUR DRESSING AND FUR DYEING 

heating. As a result of this process, a great part of the 
hematoxyhn is converted to the hematein. The logwood 
may be used for dyeing in this state as chips, but logwood 
extracts can now be obtained of a high degree of purity 
and are easier to work with. The commercial forms of the 
extract, are the liquid of 51 degrees Twaddell, and the 
solid extract. Hematein crystals can also be obtained. 
All these extracts contain mainly hematein, together 
with a small percentage of hematoxylin Avhich is con- 
verted to the former during the dyeing process. Log- 
wood is never used as a direct dye, but is used to form 
color lakes with the various mordants, the following colors 
being produced: 

Iron mordants give grey to black shades 
Copper mordants give green-blue to black shades 
Chrome mordants give blue to black shades 
Aluminum mordants give violet shades 
Tin mordants give purple shades 

By combining several of the mordants, any desired shade 
of black can be obtained, and if other dyewoods are used 
in conjunction with the logwood, the range can be further 
increased. 

Fustic, yellow- wood, or Cuba wood, as it is variously 
called, is obtained from a tree also growing in the West 
Indies, Central and South America. It is used either as 
wood chips, or as a paste extract of 51 degrees Twaddell, 
and occasionally as solid extract. Fustic contains two col- 
oring matters, morintannic acid, possessing the character- 
istics of a tannin, and which is quite soluble in water, and 
morin, which is rather insoluble, and which settles out 
from the liquid extract. Fustic is the most important of 
the yellow dyes of natural origin, and is used considerably 
in fur dyeing with logwood for shading the blacks, or for 
producing compound shades. With the usual mordants 
fustic gives the following colors: 

134 



VEGETABLE DYES 

With iron salts dark olive 

With copper salts olive 

With chrome salts olive-yellow to brownish- 
yellow 

With aluminum salts . . . yellow 

With tin salts bright yellow to orange- 
yellow 

Brazilwood, or redwood, is the product of a tree found in 
Brazil, and exists in several varieties, such as peach wood, 
Sapan wood, Lima wood, and Pernambuco wood. They 
all yield similar shades with the various mordants, and all 
seem to contain the same coloring principle, brasilin, which, 
like the hematoxylin, has no dyeing power, but by fermen- 
tation and oxidation it is converted to brasilein, corres- 
ponding to the formation of hematein. Brazilwood and 
the related woods are used either as chips or extract, but 
seldom alone, usually in conjunction with other dyewoods. 
By combining logwood, fustic and Brazilwood in various 
proportions, and by employing suitable mordants, all the 
shades required by the fur dyer can easily be produced. 

Quercitron is the inner bark of a species of oak (Quercus 
tinctoria) found in the United States. It contains two 
coloring principles, quercetrin and quercetin. The fresh 
decoction of quercitron bark is a transparent dull orange- 
red which soon becomes turbid and deposits a yellow 
crystalline mass. It is generally used in conjunction with 
other dyes. 

Cutch is the dried extract obtained from a species of 
acacia, the principal varieties being Bombay, Bengal, and 
Gambler cutch. It contains two coloring principles, cate- 
chin and catechu-tannic acid. Cutch acts as a tannin, and 
like other tannins discussed above, can be used for the pro- 
duction of grey or black shades with iron mordants. It is 
employed chiefly, however, for dyeing browns. Aluminum 
salts give with cutch a yellowish-brown, tin salts give a 

135 



FUR DRESSING AND FUR DYEING 

lighter yellow, copperas gives a brownish-grey, and chrome 
and copper salts give brown shades. 

Turmeric is the underground stem of the curcuma tinc- 
toria, the coloring principle being called curcumin. It may 
be used as a direct dye, but usually a mordant is used. 
Turmeric is sometimes used in place of fustic. 

While the tannins can be used alone with an iron mor- 
dant for producing greyish to black shades, the dyewoods 
alone yield colors which would be too bright to be suitable 
for dyeing furs. In order to tone down this brightness, and 
to give to the dyeings that greyish undertone which is 
characteristic of the natural furs, and which can only be 
imitated by means of the iron-tannin compound, it is cus- 
tomary to combine the tannins with the wood dyes. The 
iron-tannate constitutes the foundation of the color which 
gets its intensity, and necessary brilliancy and bloom from 
the wood dyes. Moreover, the presence of the iron-tannin 
compound helps considerably to increase the fastness of 
the dyeing. Furs dyed with the combination of the tan- 
nins and the wood dyes obtain an additional tanning treat- 
ment which materially improves the quality of the leather, 
for not only do the tannin substances exert this tanning 
action, but the dyewoods as well, for they are themselves 
either of the nature of tannins, or contain a coloring prin- 
ciple which is a tannin. It is to the combined effects of 
the tannin substances and the dyewoods that furs dyed with 
vegetable dyes owe their beauty of color, lustre, naturalness 
of shade, permanence of the dyeing, and durability of the 
leather. Wood dyeings on furs have for this reason ac- 
quired a just renown, but owing to the introduction of the 
new kinds of fur dyes, the use of the vegetable dye sub- 
stances has been greatly reduced. 

The dyes of vegetable origin can be applied to furs by 
either the brush method or the dip method, or both, and 
since mordants are required with the dyes of this class, 
they are applied in one of the three ways mentioned in a 

136 



VEGETABLE DYES 



previous chapter: first, by mordanting before dyeing; sec- 
ond, by applying mordant and dye simutaneously ; and 
third, by mordanting after the skins have been treated 
with the dye. 

I. Dyeing with Vegetable Dyes by the 
Brush Method 

The use of the brush method in applying the natural 
dyes to furs is limited to a comparatively few kinds of 
dyeing, namely to produce special effects on furs, or to give 
to the upper-hair of furs a coat of dye different from the 
base color. In a quite recent German patent is described 
a process for blending a red fox as a silver fox and the 
procedure affords a good example of brush dyeing with 
preliminary mordanting. The specification is as follows: 
" D. R. P. 310, 425 (1918). A process for dyeing red fox 
as silver fox. The tanned and dressed skin is first super- 
ficially decolorized by applying a dilute mixture of milk of 
lime, iron vitriol and alum, with a soft brush so as only 
to penetrate the top-haiT. Allow to remain for 4—6 hours, 
dry, and beat out the dust. A dilute solution of iron vitriol 
is brushed on so as only to wet the top-hair, and the skin 
is thus allowed to remain moist for 12-24 hours. Then 
without drying, a solution of iron vitriol, salammoniac, 
litharge, red argol and wood ashes is brushed on cold with 
a hard brush so as to penetrate all the hair down to very 
near the skin. The skin has now completely lost its red 
color, and has become a pale yellow. It is now ready to be 
dyed. An infusion of roasted nutgalls, which have been 
boiled for 3^ hours with water, is applied cold with a soft 
brush to the upper hair. Allow to remain so for 2-3 hours, 
and without drying, apply a weaker solution of the roasted 
nutgalls with a hard brush so as to saturate the hair thor- 
oughly. Dry and beat out. According to the concentration 
of the solution applied, the hair will be colored blue-grey 

137 



FUR DRESSING AND FUR DYEING 

to black, and the shade can be varied by varying the 
strength of the solutions used. The different parts of the 
skin, or those parts of different shades can be dyed accord- 
ingly." 

. In this patent all the operations, including killing, mor- 
danting and dyeing are done by the brush method, and the 
process, from this point of view is quite similar to one 
which might have been employed a century previous. It 
is evident that the time and effort required to carry out 
the details as described in the patent would only be war- 
ranted in exceptional cases, where the value of the dyed 
fur would be considerably greater than that of the natural 
skin. 

An example of the application at the same time of dye 
and mordant by the brush method is the original French 
Seal dye, which is still employed to a limited extent to 
produce a brilliant, deep, lustrous black topping on furs 
which have already been dyed by the dip process. A typi- 
cal formula for the old French Seal dye is the following: 

Green copperas 10 parts 

Alum 10 " 

Verdigris 10 " 

Gall-nuts 80 " 
Logwood extract 

(15 degrees Twaddell) 150 " 

Water 1000 " 

This mixture is applied to the top of the hair of the furs, 
after previous killing, and the skins allowed to remain 
moist for several hours, and also exposed to the air. The 
skins are then dried, and beaten out, and if necessary a 
second coat of dye is brushed on. In dyeing seal-imitation 
on muskrat, or skunk-imitation on opossum, for example, 
the black color required on the top-hair, or the upper part 
of the hair when the furs are sheared, can be produced 
by applying a mixture similar to the above, to the furs 

138 



VEGETABLE DYES 



after they have received their base color by the dip process 
with natural dyes or with the Oxidation Colors. Occasion- 
ally, the dyeing is given an after-treatment with a dilute 
solution of sodium bichromate to help develop the color, 
the action in this case being that of an oxidizing agent, and 
not of a mordant. 

As far as the third method of mordanting is concerned, 
that of first applying the dye, and then the mordant, it is 
rarely practised with the brush method. The procedure, 
however, consists in first brushing on a solution of the de- 
sired dye, then drying and brushing on a mordant solution. 
These operations are repeated perhaps two or three times 
until the proper shade is obtained, exposing the furs to the 
air for the color to be developed. 

II. Dyeing with Vegetable Dyes by the 
Dip Method 

It was in the application to furs by the dip process that 
the use of the vegetable dyes attained great importance, 
and although at the present time, natural organic dyes 
have largely been superseded by the Oxidation Colors and 
Aniline Black dyes, yet for certain purposes, and especially 
for the production of blacks, the wood dyes still are able 
to hold their own. 

The dyeing of black formerly constituted probably the 
most important branch of the fur dyeing industry, and 
was undoubtedly the most difficult one. For it is possible 
to obtain as many different kinds of black as there are 
dyers of this color, but only a few certain shades are desir- 
able. The division of the classes of furs into those derived 
from the various kinds of sheep, and those obtained from 
other animals is particularly marked in the dyeing of black, 
and both the composition of the dye formulas and the 
methods of dyeing are somewhat different for the two 
groups. For the dyeing of black on Persian lambs, broad- 

139 



FUR DRESSING AND FUR DYEING 

tails, caraculs, etc., a combination of logwood and nut- 
galls with the requisite mordants is used, while on hares, 
Chinese sheep, foxes, raccoons, opossum, etc., a mixture 
of logwood and turmeric or fustic, with the proper mor- 
dants is used. 

The general procedure is as follows : The dye substances 
to be used are ground up to a powder in a mill constructed 
for the purpose, after which they are boiled with water in 
a copper-lined kettle or cauldron, heated from the outside 
by steam. The customary arrangement is to have a jack- 
eted kettle, supported on a stand, and having taps and 
valves to enable the liquor to be drawn off, or pivoted, so 
that the kettle can be tilted, and the contents poured out. 
The use of the copper-lined vessel is to be preferred, as it 
is unaffected by any of the dye substances, and so cannot 
cause any rust stains. After the dyes have gone into solu- 
tion and have cooled, the mordant chemicals, previously 
dissolved in water, are added, and the mixture stirred up. 
The dyeing in this instance is effected by the simultaneous 
application of dye and mordant. The dye mixture is now 
run off, or poured out in the proper quantity into a number 
of small vats of 25-30 gallon capacity, or into a paddle vat, 
which can be closed, while the paddle is rotating. The lat- 
ter device is to be preferred because it permits the dye to 
retain its temperature better and for a longer period of 
time, but when lambs are being dyed only the open vats 
are used. The temperature of the dye mixture is between 
40° and 45° C, for only at this temperature can the hair 
absorb the dye properly without injuring the leather. The 
killed skins are immersed in the dyebath for a time, usually 
overnight, after which they are removed, drained and hung 
up, with the hair-side exposed to the air, so as to permit 
the dye to develop, which takes place with the aid of the 
atmopheric oxygen. The dyebath is again brought to the 
proper temperature, and the skins are again entered, to go 
through the same process as often as is necessary to obtain 

140 



VEGETABLE DYES 



the desired depth of shade. The dyed skins are thoroughly 
washed to remove excess dye, then dried and finished. The 
following are a few dye formulas used in the production of 
blacks : 

Logwood extract 100 grams 

Chestnut extract 14 c.c. 

Turmeric 38 grams 

Iron acetate 6° Be 50 c.c. 

Water 1200 c.c. 

or, 

Cutch 15 grams 

Soda 14 grams 

Logwood extract 120 grams 

Verdigris 19 grams 

Iron acetate 5° Be. 16 c.c. 

Water 1200 c.c. 

A recently published formula for dyeing China goat skins 
black, is the following: 

Dissolve 50 lbs. of dark turmeric and 45 lbs. of logwood 
extract and make up to 300 gallons of solution, at 95° F. 
Enter the killed skins and leave them in the liquor until 
they rise to the surface. Then take them out and add 25 
lbs. of logwood extract, 10 lbs. of sumach, 10 lbs. of blue 
vitriol, 5 lbs. of fustic extract, and about 60 lbs. of iron 
acetate liquor. Stir up well, and immerse the skins for 18 
hours. Draw them up, and expose to the air for 12 hours. 
Heat the liquor again to 95° F. and put the skins back for 
12 hours. Draw out, hang up in the air for a time, then 
wash thoroughly, hydro-extract, dry and finish. 

In a German patent, D. R. P. 107,717 (1898), is de- 
scribed a method for dyeing lambs black, consisting in 
treating the skins for 24 hours in a logwood bath, then 
rinsing in cold water, and mordanting for 15 hours in a 
solution of bichromate of potash. The skins are then 
washed and treated with a solution of iron salt, then dried. 

141 



FUR DRESSING AND FUR DYEING 

This process, while of not much practical importance, is 
an illustration of mordanting subsequent to the dyeing 
treatment. 

As far as the production of other shades is concerned, 
the procedure is quite similar to the regular black method. 
For a dark brown, for example, the skins are dyed in a 
mixture containing 

Gall-nuts 40 parts 

Verdigris 10 " 

Alum 10 " 

Copperas 5 " 

Brazilwood extract 

(15° Twaddell) 150 " 

Water 1000 " 

employing operations just as in the case of the black. 

Greyish-blue shades on white hares, lambs, kids, etc., can 
be obtained by treating the skins successively in the follow- 
lowing baths: 

1. Logwood extract 100 grams 
Water 1 liter 

2. Indigotine 10 grams 
Alum 10 grams 
Water 1 liter 

Bluish-grey tones on the same furs can be produced by 
treating with 

1. Logwood extract 200 grams 
Indigotine 15 grams 
Water 1 liter 

2. Alum 150 grams 
Salammoniac 12 grams 
Water 1 liter 

142 



VEGETABLE DYES 



Similar grey shades can be produced by mordanting 
the skins with an iron salt, and then dyeing in a weak 
bath containing gall-nuts, sumach and iron vitriol. This 
method is very effective for making Alaska or silver fox 
imitations. 



143 



CHAPTER XIV 
FUR DYEING 

Aniline Black 

FUR seal for a long time has been a fur of distinction 
and importance in the fur industry, and consequently 
the dyeing of seal has constituted an important, 
though not very extensive branch of the art of fur dyeing. 
In quite recent times the popularity of seal has become so 
great that imitations have had to be produced to help supply 
the demand, and as a result, French seal, or seal-dyed 
rabbit, and the so-called Hudson seal, which is seal-dyed 
muskrat, have acquired a great vogue. Occasionally opos- 
sum, nutria and other furs are also used for the purpose 
of producing seal imitations. While the supply of real 
seals is relatively small, and the demand large, the pro- 
duction of seal imitations has assumed large proportions, 
and as a result, the dyeing of seal and its imitations or 
substitutes has come to be a great branch of the fur dyeing 
industry. 

During the past thirty years, the long and tedious proc- 
esses of dyeing seal and seal imitations, involving the use 
of dyes of vegetable origin, have largely been superseded 
by what is known as the Aniline Black dye. It was the 
French who first worked out successfully the application 
of Aniline Black to furs, and the method has attained much 
importance and extensive use in the fur dyeing industry. 

Aniline Black is the name given to an insoluble black 
dyestuff produced by the oxidation of aniline in an acid 
medium. As a finished product it cannot be used in fur 
dyeing, but if the hair of the furs be impregnated with a 

144 



ANILINE BLACK 



suitable preparation of aniline and then treated with cer- 
tain oxidizing agents, the color will be formed on the hair, 
being firmly fixed and giving a fast black, resistant to 
light, washing and rubbing. The basis of the dye, aniline, 
is an oily liquid, possessing a peculiar fishy odor, colorless 
when pure, but rapidly turning brown when exposed to the 
air. It is obtained from benzol, which is distilled from 
coal-tar, by treating with nitric acid, forming nitrobenzol, 
which when subjected to the action of reducing chemicals 
is converted into aniline. The process may be shown 
schematically as follows: 

Coal — coal-tar — benzol — nitrobenzol — aniline oil — 
Aniline Black. Aniline Black was by no means a new dye 
when the French succeeded in producing it on furs. It had 
been used for a long time previous on textiles, chiefly cotton. 
The history of the development of the Aniline Black proc- 
ess throws considerable light on its nature and constitu- 
tion, and so presents many features of interest. As early 
as 1834, the chemist Runge observed the formation of a 
dark green color when heated aniline nitrate in the pres- 
ence of cupric chloride. Fritsche, in 1840, noticed that 
when chromic acid was added to solutions of aniline salt, 
a dark green, and sometimes a blue-black precipitate was 
produced, and later the same chemist obtained a deep blue 
by the action of potassium chlorate on aniline salt. It is 
interesting to note that Perkin, in 1856, conducting simi- 
lar experiments on the oxidation of aniline with chromic 
acid, obtained a blue-black product from which he extracted 
the first synthetic coal-tar dye, mauve. Thus far, all the 
experiments on the oxidation of aniline proved to be merely 
of scientific interest, but in 1862, Lightfoot patented a 
process for the practical application of colors formed by 
the oxidation' of aniline on the fibre, a greenish shade being 
obtained by that method, to which the name emeraldine 
was given, and by subsequent treatment with bichromate 
of potash, the green was changed to a deep blue color. 



145 



FUR DRESSING AND FUR DYEING 

Since that time, the methods for producing and applying 
Aniline Black have been developed and improved, although 
all the processes were based on the principles incorporated 
in Lightfoot's original patent. However, it was not until the 
last decade of the nineteenth century that the dyeing of 
furs by means of the Aniline Black method was successfully 
attempted. 

A knowledge of the nature and the manner of the chem- 
ical changes which take place in the production of Aniline 
Black is a valuable aid in obtaining satisfactory results 
in practise; and although Aniline Black was extensively 
used before the true character of the reaction was under- 
stood, since the successful determination of the constitu- 
tion of Aniline Black and the discovery of the real nature 
of the process by Green and his collaborators in 1913, the 
methods have been considerably improved and simplified, 
with correspondingly better results in dyeing. As a conse- 
quence, the methods of dyeing furs with Aniline Black have 
also become simpler and more efficient. 

A discussion of the chemical changes which occur in the 
Aniline Black process, is out of place here on account of 
the highly involved and complicated character of the reac- 
tions, to understand which requires a considerable knowl- 
edge of specialized organic chemistry. But the essential 
features of practical importance in the production of Ani- 
line Black are the following: As already noted, one of 
the characteristic properties of aniline is its tendency to 
turn from a colorless to a dark-brown liquid in the pres- 
ence of the air. This change is due, together with certain 
other causes, to an oxidation brought about by atmospheric 
oxygen. By employing oxidizing agents, this oxidation 
can be accelerated and carried further, and eventually the 
Aniline Black is obtained. Among the substances which 
may be used to bring about the conversion of aniline to 
the insoluble black dye are manganese dioxide, lead perox- 
ide, hydrogen peroxide, chromic acid, ferric salts, potassium 

146 



ANILINE BLACK 



permanganate, chloric acid and chlorates in the presence 
of certain metallic salts, particularly those of vanadium and 
copper. Chlorates, especially sodium chlorate and potas- 
sium chlorate, are the most commonly employed oxidizing 
agents, bichromate of soda or of potash being used, in 
addition, to complete the oxidation. When using chlorates 
it is necessary to have present in the dye mixture a small 
quantity of a metallic salt, which, while not entering into 
the reaction itself, is nevertheless indispensable as an oxy- 
gen carrier. Vanadium compounds have proved to be the 
most effective for this purpose, and according to an author- 
ity, one part of vanadium salt is sufficient to cause the 
conversion of 270,000 parts of aniline to Aniline Black, the 
necessary amount of a chlorate being present of course. 
Salts of copper, cerium, and iron are also extensively used, 
but they are not quite so efficient as vanadium. 

The formation of the Aniline Black in practise takes place 
in three well-defined steps, which it is important to be 
able to recognize and distinguish in order to obtain the best 
results. The first stage of the oxidizing process produces 
what is called emeraldine, which in the acid medium of the 
aniline bath is of a dark green, while in the free state it is 
of a blue color. As the oxidation proceeds, the second stage 
develops, the emeraldine being converted to a compound 
called nigraniline. This in acid solution is blue, and the 
free base is a dark-blue, almost black. It was formerly 
considered that the nigraniline was the Aniline Black 
proper, and so when this stage of the oxidation was reached, 
the process was often interrupted and not carried to the 
limit. This can account for the fact that Aniline Black 
dyeings usually turned green after a short time. The 
reason for this is that nigraniline, when treated with weak 
reducing agents, as, for example, sulphurous acid, is at once 
changed to emeraldine, with its dark green color. Since 
there is usually a small amount of sulphurous acid in the 
air, especially in places where coal or gas is burned, an 



147 



FUR DRESSING AND FUR DYEING 

Aniline Black dyeing which has not been carried beyond 
the nigraniline stage will be reduced in time to the emerald- 
ine, and cause the dyeing to become green. The last step 
in the oxidation changes the nigraniline into what is prop- 
erly called the ungreenable Aniline Black. Weak reducing 
substances like sulphurous acid do not change this com- 
pound to emeraldine, and stronger reducing agents only 
convert it to a brownish compound, which changes back 
to the black when exposed to the air. It is quite evident 
that in order to obtain a black which will not change to 
green in time, the oxidation of the aniline must be carried 
to the last stage. By making tests during the dyeing of 
the furs, it can easily be determined whether the oxidation 
has proceeded far enough. 

In the dyeing of textiles with Aniline Black, it is custom- 
ary to carry out the operation at comparatively high tem- 
peratures, approaching 100° centigrade. With furs such 
temperatures are out of the question, so it is necessary to 
repeat the dyeing several times in order to obtain the 
proper depth of shade working in the cold. Only the brush 
method can be used in applying the Aniline Black dye to 
furs, on account of the strong acidity of the dye mix- 
ture, which would ruin the leather, if the dyeing were done 
in a bath. Indeed, great care must be exercised even by 
the brush method to avoid too great penetration of the 
dye liquid, otherwise the roots of the hair will be attacked, 
and the leather may be " burned " from the hair side. Furs 
dyed with Aniline Black are frequently after-dyed by the 
dip-process with logwood or some other similar dye, in order 
to add to the brilliancy of the dyeing. Combined with in- 
tensity of color. Aniline Black on furs is the only dye which 
will also give fast, lustrous shades, and leave the hair soft 
and smooth. 

There are several methods of applying Aniline Black on 
furs, the most important being 



148 



ANILINE BLACK 



1. One-bath Aniline Black 

2. Oxidation Aniline Black 

3. Diphenyl Black 

4. Aniline Black by Green's Process 

1. One-bath Aniline Black 

A typical formula for this method is the following given 
by Beltzer: 

Aniline salt 10 kg. 

Sodium chlorate 1.5 kg. 

Copper sulphate 0.7 kg. 

Vanadate of ammonia 10 gr. 

All these substances are dissolved hot in 50 liters of water, 
and allowed to cool, forming solution A. Aniline salt is 
aniline oil which has been neutralized with the exact 
quantity of hydrochloric acid to form the hydrochloride. 
It forms white or greyish crystalline lumps very easily 
soluble in water. The sodium chlorate is the oxidizing 
agent, and the copper sulphate and the vanadate of am- 
monia are the oxygen carriers. 

15 kg. of sodium bichromate are also dissolved in 50 liters 
of water, forming solution B. The bichromate is also an 
ozidizing agent and serves to complete the oxidation of the 
aniline to the black. 

Immediately before using, solutions A and B are mixed 
together, both being cool. In general practise it is cus- 
tomary to mix only small quantities at a time, as a con- 
siderable precipitate forms when the whole batch is mixed 
at once, the precipitate being so much waste dye substance. 
Usually a liter of A and a liter of B are mixed at a time, 
and the furs brushed with the mixture. The brushing must 
be varied according as the hair is hard and stiff, or soft and 
tender. The hair must be thoroughly impregnated in all 

149 



FUR DRESSING AND FUR DYEING 



directions, and the penetration must not be too deep to 
affect the leather. With experience and dexterity satis- 
factory results can easily be achieved. After the skins 
have been properly treated, they are dried at a temperature 
of about 35 degrees centigrade. When dry, they are re- 
turned to the dye bench, where they receive another appli- 
cation of the dye mixture, and are again dried. This opera- 
tion may be repeated as often as six or seven times before 
a sufficiently intense black is obtained. Another way of 
producing the desired depth of shade with fewer applica- 
tions is by using more concentrated dye mixtures. Each 
method has its disadvantages, the greater number of brush- 
ings requiring the expenditure of more time and labor, and 
the greater concentration of the bath resulting in a con- 
siderable loss of dye substance due to the formation of a 
large precipitate when the two solutions are mixed, and 
moreover, not all furs can be treated with concentrated 
mixtures. The best results with this method usually re- 
quire the application of six coats of a mixture of moderate 
concentration. 

2. Oxidation Anilijie Black 

In order to overcome the difficulty of employing very 
concentrated dye mixtures, or of making many applications 
of the dye, a method was devised whereby the two solutions 
of the previous- process, instead of being mixed together, 
are applied successively to the hair of the furs, the following 
formula, also by Beltzer, being an example: 

Aniline oil 10 liters 
Nitric acid 36° Beaume, or 

Hydrochloric acid 22° Beaume 20 liters 

Cold water 20 liters 

This is solution A, and is merely a solution of aniline 
hydrochloride, or nitrate, depending on which acid has been 

150 



ANILINE BLACK 



used. Nitric acid, although more costly than the hydro- 
chloric acid, is to be preferred, because it is an oxidizing 
acid, and so assists in the oxidation of the aniline, and be- 
sides, has a more beneficial effect on the hair than the hydro- 
chloric, in the matter of softness and luster. 



Sodium chlorate 


4 kg. 


Copper sulphate 


1 kg. 


Vanadate of ammonia 


10 gr. 


Water 


50 liters 



This is solution B, containing the oxidizing agent, and the 
oxygen carriers. Just before using, equal quantities of A 
and B are mixed, and the skins brushed with the mixture. 
The skins are then dried at 35-45° centigrade, at which 
temperature the color begins to develop. When almost, 
but not entirely dried, the skins are subjected to the action 
of warm vapor, which is allowed to enter the drying 
chamber, so as to keep the temperature about 40° centi- 
grade, the color developing better in this way. This opera- 
tion may be repeated, or the skins are directly treated with 
a solution of 25 kg. of sodium bichromate in 100 liters of 
water, to complete the oxidation. The moist skins are ex- 
posed to the air for a time, and then dried at 35° C. 

This method of dyeing has several advantages over the 
One-bath Aniline Black. It requires fewer brushings, and 
enables the complete utilization of the dye solutions with- 
out loss. With three applications of the dye mixture by 
the Oxidation process, as deep and intense a black can be 
obtained as with six brushings by the One-bath method. 
The dyeings, too, are nearly, but not fully as brilliant and 
even as in the latter case. The greater the number of 
coats of dye that are applied the more regular will the 
dyeing be. 



151 



FUR DRESSING AND FUR DYEING 

3. Diphenyl Black 

In 1902, the Farbwerke Hoechst, a large German producer 
of coal tar intermediates and dyes, invented an Aniline 
Black process to which they gave the name Diphenyl Black. 
The chief departure from the previous Aniline Black 
methods was the replacing of part of the aniline oil of the 
dye mixture by Diphenyl Black Base I, which is para- 
aminodiphenylamine. This base has the property of being 
oxidized to Aniline Black, just like aniline oil, and the ad- 
vantage claimed for the Diphenyl Black is that it produces 
an absolutely ungreenable black. The method of application 
is practically the same as for the other Aniline Black proc- 
esses, chlorates being used as the oxidizing agents, in the 
presence of oxygen carriers such as salts of copper and van- 
adium. The use of bichromates is dispensed with. On 
account of the comparatively high cost of the Diphenyl 
Black Base I, this method has not found very extensive 
application, especially as highly satisfactory ungreenable 
blacks can now be produced by other methods. 

4. Aniline Black by Green's Process 

In 1907, Green, who has done much work in the direction 
of elucidating the character of the Aniline Black process, 
obtained a patent for a method of applying Aniline Black 
in a manner which was different from all the previously 
known formulas. The invention created great interest, 
and although in its original form it did not find a wide 
application, many of the methods used at the present time 
are in one way or another derived from the idea of Green. 
A resume of the patent will therefore be given here: " The 
invention relates to the production of an Aniline Black, the 
new process differing from all other known processes by the 
fact that the oxidation of aniline is effected solely or 
mainly by the oxygen of air. The possibility of dispensing 

152 



ANILINE BLACK 



with an oxidizing agent depends on the discovery that the 
addition of a small quantity of a para-diamine, or of a para- 
amido-phenol to a mixture containing aniline and a suit- 
able oxygen carrier, such as a salt of copper, greatly acceler- 
ates the oxidation of the aniline by the atmospheric oxygen. 
Further, whereas in the ordinary processes of Aniline Black, 
the quantity of mineral acid employed cannot be materially 
reduced below the proportion of one. equivalent to one 
equivalent of the base, under the new conditions the 
mineral acid may be wholly or partially replaced by an 
organic acid such as formic acid, without the quality of the 
black being materially affected. As suitable oxygen carriers 
the chlorides of copper have been found to give the best 
results, it being preferrable to use the copper in the form 
of a cuprous salt. This is effected by adding to the dye 
mixture cupric chloride, together with a sulphite or bi- 
sulphite in sufficient quantity to reduce the cupric salt to 
the cuprous state, and a sufficient quantity of a soluble 
chloride to keep the cuprous chloride in solution. Among 
the compounds suitable for the production of this black in 
conjunction with aniline are, para-phenylene-diamine, di- 
methyl-para-phenylene-diamine, para-amido-diphenylam- 
ine, para-amido-phenol, etc.," 

This method may be used alone as the other Aniline 
Blacks, or the dyed skins may be after-dyed in a bath con- 
taining a logwood dye, or it may be used in conjunction 
with mineral dyes, or with the Oxidation Colors, (see next 
chapter). A typical formula for the black by Green's 
process is the following: 



Para-amido-phenol 


0.5 kg. 


Aniline oil 


10 liters 


Hydrochloric acid 22° Be. 


10 liters 


Acetic acid 40% 


5 liters 


Cold water 


25 liters 



153 



FUR DRESSING AND FUR DYEING 



This is solution A. Solution B is prepared by dissolving 

Copper sulphate 2 kg. 

Salammoniac 10 kg. 

Cold water 50 liters 

A and B are mixed, and the mixture applied to the hair of 
the furs several times, dryig each time at 35°-40° C. After 
three coats of dye have been applied, a pretty and fairly 
intense black shade is obtained, which is developed further 
by treating with a solution of 25 grams of sodium bichro- 
mate per liter of water. The skins are then allowed to 
dry in air, and then if desired, an after-dyeing is made with 
some other dye. 

On account of its extreme fastness. Aniline Black, pro- 
duced by any of the methods outlined above, has attained 
a justifiable popularity for the dyeing of furs, in spite of the 
necessity of using the more or less cumbersome brush 
method of applying the dye. Very recently there was issued 
to a German company a patent in which is described a 
method whereby furs can be dyed with Aniline Black by the 
dip process. An abstract of the patent (D. R. P. 33402) is as 
follows: ''As is known, aniline salt, and similar salts, to- 
gether with oxidizing agents like bichromates, chlorates, 
etc., cannot be used for dyeing furs by the dip process, be- 
cause the strongly dissociated mineral acid is injurious to 
the leather. The dissociation of the acid can be reduced 
by adding neutral salts, like common salt, or Glauber's salt, 
so that good results can be obtained by dyeing in a bath of 
the dye mixture, the leather retaining its softness." 

Thus far there have been no reports of the successful 
practical application of this patent, so its value cannot be 
discussed. It is extremely doubtful, however, that furs 
will ever be dyed in the dyebath with the present type of 
Aniline Black formulas, no matter what substances are 
added to prevent the leather from being affected. 

154 



CHAPTER XV 

FUR DYEING I 

Oxidation Colors 

THE year 1888 may be considered the beginning of 
a new era in the history of fur dyeing; the com- 
mencement of a period which was to see the time- 
honored, traditional methods of the masters of the art give 
way to newer methods of an entirely different character; 
and moreover, the initiation of an age when science with 
its basis of fact and logic, was to undertake the rationaliza- 
tion of an industry which had hitherto worked upon a more 
or less irrational, empirical and uncertain comprehension of 
the fundamental principles involved. It was not the work 
of a single day, or even of a year which brought about the 
virtual revolution in the dyeing of furs, but the result of 
long, patient, systematic effort. About this time, the 
German coal tar industry was attaining its real stride along 
the path of progress and achievement, and had already 
succeeded in reaching, to an appreciable degree at any rate, 
most users of coloring matters, with the consequence that 
the natural dyes, with their time and labor-consuming 
processes of application were gradually being superseded by 
the new synthetic dyestuffs which could be simply and 
quickly applied. It was now the turn of the fur dyeing 
industry to receive the attention of the scientists and tech- 
nologists responsible for the growth of the coal tar dye in- 
dustry, and so there appeared in the above-mentioned year, 
the following patents, taken out by a German chemist 
named Erdmann: 

D. R. P. 47349 
A Process for Dyeing Hair and Feathers 

155 



FUR DRESSING AND FUR DYEING 



If white hair or feathers are soaked in an aqueous or 
alcoholic solution of para-phenylene-diamine, and then ex- 
posed to the slow oxidation of the air, or are treated in a 
second solution with some oxidizing agent, then the hair 
or feathers will be dyed. According to the oxidizing agent 
chosen, and the concentration of the solution used, the color 
obtained will be light or dark, varying from the palest blond 
to the deepest blue-black. Particularly suitable as oxid- 
izing substances are ferric chloride, permanganates, chlo- 
rates, hypochlorites, bichromates, and hydrogen peroxide. 
The dyeings are fast, that is, they do not come off, and the 
color cannot be removed by washing. Following examples 
may serve to make the process clear : 

20 grams pure para-phenylene-diamine and 14 grams 
caustic soda are dissolved in a liter of water. The hair, 
previously degreased, is soaked thoroughly in this solu- 
tion, and while moist is entered into a three per cent 
solution of peroxide of hydrogen. The action is not 
instantaneous, but after a day, the hair is dyed a dark 
shade; by repetition of these operations a blue-black is 
obtained. 

The para-phenylene-diamine can be replaced in this proc- 
ess by other similar bases, such as dimethyl-para-phenylene- 
diamine, as well as the naphthylene-diamines. Since the 
substances which can be applied by this process are unin- 
jurious, the method described can be used to dye human 
hair on the head or beard, and so seems suited to replace 
for the dyeing of hair, the metallic salts and various pyro- 
gallic solutions which are on the market, and which are 
harmful to the health. 

D. R. P. 51073 Supplement to 47349; Process 
for Dyeing Hair 

This patent was an extension of the original patent to 
include certain oxy and amido-oxy compounds, the method 

156 



OXIDATION COLORS 



being essentially the same otherwise as in the original 
patent. An illustration of the process is as follows: 

73 grams para-amido phenol hydrochloride are dissolved 
with 40 grams caustic soda in a liter of water. The solu- 
tion dyes hair a golden-yellow, which on subsequent treat- 
ment with a solution of ferric chloride turns to a red-brown. 

In these two patents is to be found the basis of the 
modern fur dyes and fur dyeing methods. It is interesting 
to note that furs were not mentioned at all in connection 
with the process, which was intended mainly for dyeing 
hair, especially on the human head. It was only several 
years later that the value of the method for dyeing furs 
was realized. So about 1894, the Aktien Gesellschaft fiir 
Anilinfabrikation put upon the market three fur dyes 
under the trade name Ursol, Ursol D, giving dark-brown 
to black shades; Ursol P, giving red-brown colors; and 
Ursol C, giving a yellowish-brown shade. Pyrogallic acid 
had been previously used as a hair dye, and also to a slight 
extent as a fur dye, so it was used in conjunction with the 
Ursol dyes for shading purposes. The new fur dyes were not 
dyes in the ordinarily accepted sense of the term. They 
were really coal-tar intermediates, substances similar in 
character to aniline, and their dyeing property depended 
on the fact that they could be oxidized either by atmos- 
pheric oxygen, or by means of oxidizing agents, forming 
colored insoluble products. When the oxidation of the 
intermediate was caused to take place on the hair the 
colored product formed on and in the hair fibre, and re- 
mained fast. The reactions bringing about the conversion 
of the intermediate to the colored insoluble compound are 
quite analogous to those of the Aniline Black process, 
though possibly not so complicated, with the important dif- 
ference, however, that, while in the production of Aniline 
Black acid is essential, in the present instance the oxida- 
tion can be carried on in neutral or even alkaline medium. 
On account of the character of the method used in applying 



157 



FUR DRESSING AND FUR DYEING 

the new fur dyes, the name Oxidation Colors has been given 
to them. Strictly speaking, Aniline Black is also an Oxida- 
tion dye, but it is usually considered in a class by itself. 
The methods used at first in the application of the Ursol 
dyes to furs followed closely the process as described in the 
patents. The furs were first killed, usually by brushing 
on a lime mixture, drying, and then beating out the dust. 
This operation was repeated, if necessary. Then a solu- 
tion of the desired dye, mixed with an equal volume of 3% 
peroxide of hydrogen was brushed on and the fur allowed 
to lie exposed to the air. The dyeing could also be done 
by the dip process, less concentrated solutions being used. 
By varying the concentration of the solution, and prolong- 
ing or shortening the time of action, the shades could be 
varied from very light to very dark, and by combining 
two or more of the Oxidation Colors, many different color 
effects could be produced. Soon other fur dyes were de- 
veloped and put on the market; for example, Ursol DB, 
giving blue to blue-black shades, and Ursol 2G, yielding 
yellowish tones suitable for mixing with the other colors. 
Ursol C was discarded shortly after its introduction. The 
dyeings obtained with the Oxidation Colors seemed to be 
very fast, resisting successfully the action of cold or hot 
water, or even hot soap solution. Moreover, a dyed hair 
examined under the microscope appeared to be colored 
through the epidermis to the medulla, and no individual 
particles of dye could be discerned. 

The new fur dyes had many evident advantages over the 
coloring matters in general use at the time. The simplicity 
of the dyeing operations, the short duration of the process, 
the great tinctorial power of the new products, were facts 
which strongly recommended themselves to the progressive 
fur dyer. The cost of the dyes was higher than that of the 
vegetable dyes, but this consideration was largely over- 
balanced by the saving in time and labor in using them. 
And yet, the Ursol dyes found only a comparatively small 

158 



OXIDATION COLORS 



market. The majority of fur dyers, always conservative 
and reluctant to turn from the traditional ways of the in- 
dustry were skeptical of, and even hostile towards the new 
dyes and the new methods of dyeing. In a sense, this oppo- 
sition was justifiable. It was not an easy task to relinquish 
all at once methods which had been successfully applied for 
generations back, and with which they were thoroughly ex- 
perienced, in favor of processes which were radically differ- 
ent, and with which they had no experience at all. But 
some enterprising spirits among the fur dyers undertook to 
try out the new products and it was not long before the 
skeptics had good cause for condemning the work and 
achievements of the chemists as far as fur dyeing was con- 
cerned. The new type of dyes did possess some of the 
advantages claimed for them, but they also possessed many 
highly objectionable features, which had never been mani- 
fest with the vegetable dyes. First of all, the dyeings were 
not so fast as had at first appeared, for the color came off 
the hair when the furs were rubbed, brushed or beaten. 
Then it was observed that after a short time some of the 
dyeings changed color, and at the same time the hair lost 
its gloss and became brittle. The condition of the leather 
after dyeing was anything but satisfactory. Most serious 
of all, however, was the appearance among the workers in 
the dyeing establishments, and also among the furriers who 
worked with the dyed skins, of certain pathological condi- 
tions which had hitherto been unknown. Various skin 
diseases, eczemas, inflammation of the eyes, asthmatic affec- 
tions and intestinal irritations were some of the afflictions 
which were directly attributable to the use of fur dyes of 
the Ursol type. Medical science was at a loss to know how 
to treat these ailments, because their nature was not under- 
stood. 

Here indeed, were obstacles threatening to destroy all the 
hopes which the discovery of the new class of dyes had 
aroused, and to check at the outset the possibility of rational 



159 



FUR DRESSING AND FUR DYEING 

progress in the fur dyeing industry. But the men of science 
were not content to let the matter drop thus. Difficult 
problems had been solved before, and surely there must 
be some way of overcoming the objections and deleterious 
features of a system of fur dyeing which had so much po- 
tential merit. Where hindrances sprang up in the path of 
progress, it was the duty of the chemist to remove them, 
and when difficulties arose, it was up to him to resolve them, 
as far as was humanly possible. So the chemists who had 
been responsible for the introduction of the Oxidation 
Colors set themselves to the task of eliminating the un- 
desirable or injurious qualities. It was many years before 
the results of painstaking effort and persistent study cleared 
up the causes of all the objectionable aspects of the fur 
dyes, and suggested means of overcoming them satisfac- 
torily. The work had been directed to the improvement 
of the dyes and of the methods of dyeing with them. Purer 
intermediates were produced, and more easily soluble ones, 
so that there would be no possibility of ultra-microscopic 
particles of the dye being deposited on the surface of the 
hair from the dye solution, instead of being taken up within 
the hair fibre. It was this superficial deposition of minute 
crystals of the dye or of the only partially oxidized inter- 
mediate, on the hair, crystals so fine as to be invisible in 
the ordinary high-power microscope, which caused the color 
to come off when the furs were brushed or beaten, giving 
rise to a dust which was frequently very injurious to the 
health. Then, mordants were adopted to help fix the dyes, 
compounds of copper, iron, and chromium being used as 
formerly with the vegetable dyes, and the range of shades 
was also increased thereby. Certain of the Oxidation 
Colors had a tendency to sublime off the hair, so the dyed 
hair was chemically after-treated in such cases to prevent 
this. The causes of the pathological aspects of dyeing with 
the Oxidation fur dyes were not so readily disposed of. 
But the adoption of devices to prevent the formation and 

160 ' 



OXIDATION COLORS 



circulation of dust during the handling of the dye, the em- 
ployment of adequate protection against contact with the 
dye or its solutions, the use of the most dilute solutions 
possible in dyeing, the thorough washing of the dyed skins 
to remove any excess of the coloring matter, the prevention 
of dust formation in the drying of the skins, and the rigid 
observance of, and adherence to hygienic laws, were all 
factors in the elimination of the health-impairing phases 
of dyeing with the Oxidation Colors. 

It was only after all these improvements had been accom- 
plished that the fur dye intermediates began to acquire a 
degree of popularity among fur dyers, and strange as it 
may seem, there was a more ready market for these dyes 
in America, than in Germany where they were manufac- 
tured. Other manufacurers of coal-tar intermediates also 
began to produce fur dyes, and so, in addition to the Ursols, 
there were the Nako brand, the Furrol brand, the Furrein 
brand, and one or two others. New dyes were invented, 
until the whole range of colors suitable for fur dyeing had 
been produced. The black dye, however, presented some 
difficulty. A black dye which would rival logwood blacks 
could not be attained. Ursol DB in conjunction with 
Ursol D was being used to produce bluish-blacks, but the 
dyeings were not fast, turning reddish after a time. In 
1909, a patent was taken out for a dye mixture, which was 
made up like the DB brand, but instead of using toluylene 
diamine with para-phenylene-diamine, the new dye was 
made up of a methoxy, or ethoxy-diamine with para-phenyl- 
ene-diamine, and it yielded brilliant bluish-blacks, which 
were fast, and which very nearly approached the logwood 
black in luster, intensity, and bloom. For some purposes, 
however, the production of a black color is still dependent 
on. the use of the logwood dye. 

When the Great War cut off to a large degree the im- 
portation of skins dyed in Europe, the American fur dyeing 
industry developed tremendously, and in a comparatively 



161 



FUR DRESSING AND FUR DYEING 

short time was able satisfactorily to accomplish in the way 
of dyeing furs, what had taken foreign dyers a much longer 
period to attain. It had been previously considered that 
furs could be dyed properly only by European fur dyers, 
but the achievements in this direction by Americans fully 
dispelled this belief. But the success of the fur dyers in 
America might not have been so marked or rapid, had it 
not been for the work of the American chemists. The war 
had also shut off the supply of German dyes, upon which 
the dyeing industries of America had formerly been de- 
pendent, so enterprising chemists in this country undertook 
to fill the need, and in a surprisingly short time, American 
fur dyes, in every respect the equal of the foreign product 
were offered to the American fur dyers, and at the present 
time, the requirements of the fur dyeing industry in this 
country are being adequately met by domestic producers. 
Among the brands on tha market are the Rodol, Furamine, 
Furol, and several others. The Oxidation Colors are now 
being offered in a high state of purity, and easily soluble, 
free from any poisonous constituents, and there is abso- 
lutely no reason for the appearance of any pathological con- 
ditions among workers on dyed furs, or users of such furs, 
provided the necessary precautions have been taken in the 
dyeing process. The occurrence of any affection which can 
be traced to dyed fur, cannot possibly be due to the dye 
itself, but to gross carelessness and negligence in dyeing, 
and in any such event, the dyer responsible should be 
brought to account. 

In order to get a better understanding of the nature and 
action of the Oxidation Colors, a typical one will be studied 
in some detail. The most important one in this class is 
para-phenylene-diamine, usually designated by the letter D 
in all commercial brands of this fur dye, while its chemical 
formula is represented as CeHi (NHo).. When pure it 
occurs in colorless, crystalline lumps, which rapidly 
turn brown when exposed to the air; the technical 

162 



OXIDATION COLORS 



product of commerce is of a dark-brown color. It 
dissolves readily in hot water when pure, and also in 
acids. At one time the hydrochloride was used instead of 
the free base, on account of its greater solubility, but now 
a base is made which is sufficiently pure to be very soluble 
in water. There are several methods of preparing para- 
phenylene-diamine: first, by the reduction of amido-azo- 
benzol, the product obtained in this way always containing 
a slight amount of aniline, which reduces the solubility, and 
also gives rise to poisonous oxidation products during the 
dyeing process; second, by the reduction of paranitraniline, 
the quality and solubility of the product in this case de- 
pending on the purity of the starting material; and third, 
by the treatment of para-dichloro-benzol with ammonia 
under pressure, the best product being obtained by this 
method. The crude para-phenylene-diamine, made by any 
of the above processes, is generally distilled in vacuo, the 
refined base being obtained as lumps with a crystalline 
fracture. 

The first step in the oxidation of the para-phe- 
nylene-diamine is the formation of quinone di-imine, 
NH:CoH4:NH. This is a very unstable compound in the 
free state, and even in aqueous solution it decomposes 
within a comparatively short time, or combines with itself 
to form a more stable substance. Quinone di-imine has a 
very sharp, penetrating odor, and produces violent local 
irritations wherever it comes in contact with the mucous 
membrane. If a small quantity of para-phenylene-diamine 
is absorbed into the human body, by breathing the dust, 
or otherwise, the formation of quinone di-imine takes place 
internally with consequent irritation of the mucous lining 
throughout the body. The various pathological conditions 
mentioned before may be ascribed to irritation caused by 
quinone di-imine. In any dyeing process where there is a 
possibility of the formation of quinone di-imine, as is the 
case with most dyes containing para-phenylene-diamine, 



163 



FUR DRESSING AND FUR DYEING 

special precautions must be taken by the workers in hand- 
ling the dye or coming in contact with its solutions, and no 
one who is particularly sensitive to irritation should be per- 
mitted to work in a place where such dyes are used. 

The next step in the oxidation of the para-phenylene- 
diamine is the formation of what is called Bandrowski's 
base. Three parts of the quinone di-imine combine with 
themselves, forming a substance of a brown-black color, 
which was formerly regarded as the final oxidation product. 
The formula of Bandrowski's base is represented by the fol- 
lowing chemical hieroglyphics: 

(NH,),.CeH3.N:CoH,:N.CeH3(NH.),. 

Further investigation has shown that the oxidation pro- 
ceeds beyond this stage with the formation of a compound 
of what is known as the azine type, which is depicted by the 

chemist as (NH3).CeH3 <S§>CeH.<NH>CeH3.NH,. 

It is by no means certain that this substance is the true 
coloring matter obtained by the oxidation of para-phenyl- 
ene-diamine, for the reactions may continue still farther, 
producing even more complicated oxidation products. 
Scientific research and study has not as yet gone beyond 
this stage. 

The reactions of the other dyes of the Oxidation type are 
quite similar to those of para-phenylene-diamine, some 
being simpler, and others being even more complex. The 
presence of certain chemical groups in the intermediate, 
or the relative position of such groups are factors re- 
sponsible for the variations in shade. 

With the various mordants, the Oxidation Colors give 
different shades, and a great range of colors can be produced 
either by combining mordants, or combining dyes, or both. 
The following tables illustrate the shades formed with the 
customary mordants. 



164 



OXIDATION COLORS 





Chbome 


Copper 


Iron 


Direct 


Ursol D 


brown black 


coal black 


coal black 


dark brown to 
brown black 


Ursol P 


dull red brown 


dull dark brown 


grey brown 


light brown 


Ursol 2G 


yellow brown 


d u 1 1 y e 1 1 w 
brown 


yellow brown 


dull yellow 


Ursol A 






blue black 


blue to blue- 








black 


Ursol 4G 


light brown 


medium brown 


yellow 


pure yellow 


Ursol 4R 


orange brown 


light yellow 
brown 


red brown 


orange red 


Ursol 










Grev B 


greenish grey 


greenish grey 


mouse grey 




Ursol 




Grey R 


brownish grey 


brownish grey 


reddish grey 







Fur dyes of American make being equal in every way to 
the German product, show the same color reactions with the 
various mordants. The following table shows the shades 
produced with the same mordants as above: 



Chrome 



Copper 



Iron 



Direct 



Rodol D 
Rodol P 
Rodol 2G 
Rodol 4G 
Rodol A 
Rodol 

Grey B 
Rodol 

Grey R 



brown black 
red brown 
yellow brown 
light brown 



greenish grey 
greenish grey 



coal black 
dark brown 
yellow brown 
light brown 
blue black 

greenish grey 

brownish grey 



coal black 
grey brown 
yellow brown 
reddish brown 



mouse grey 
mouse grey 



brownish black 
light brown 
dull yellow 
pure yellow 
blue black 



All these shades are produced by dyeing in a bath con- 
taining a 7ieutral solution of the dye. Sometimes the dye 
comes in the form of a salt of a mineral acid, like hydro- 
chloric or sulphuric acid, in which case a sufficient amount 
of an alkali, usually ammonia, is added to liberate the free 



165 



FUR DRESSING AND FUR DYEING 

base. According to the Cassella Co., German manufac- 
turers of the Furrol brand of fur dyes, the dyeing can also 
be carried on in slightly alkaline or in slightly acid solution, 
a different series of shades being obtained in each instance. 
Ammonia is used to render the bath alkaline, and formic 
acid to make it acid. The most customary practise, how- 
ever, is to use neutral solutions of the dyes. 

For preparing the mordant solutions much smaller 
quantities of the metallic compounds are used than in the 
case of the vegetable dyes. With chrome mordants cream 
of tartar is always employed as an assistant, and occasion- 
ally also with copper and with iron mordants. With copper, 
and also with iron mordants no addition is made at all, or 
sometimes a small quantity of acetic acid is added. The 
temperature of the mordant solution is kept about 30° C, 
and the duration of the mordanting varies from 2-24 hours 
according to the depth of shade desired. The concentra- 
tion of the solution may also be varied, it sometimes being 
just as well to use a strong mordant solution and less dura- 
tion of mordanting. Chrome may be combined with 
copper, and iron may be combined with copper, but chrome 
and iron do not go together as mordants. Some typical 
average mordanting formulas are as follows : 

Chrome mordant. 

Bichromate of soda 2.5 gms. 

Cream of tartar 1.5 gms. 

Water 1 liter 

Copper mordant. 

Copper sulphate 2 gms. 

(Acetic acid 50% 2 gms.) 

Water 1 liter - 



166 



OXIDATION COLORS 



or, 



Iron mordant. 

Ferrous sulphate 2 gms. 

(Acetic acid 50% 2 gms.) 

Water . 1 liter 

Iron pyrolignite 30% 10 gms. 
Water 1 liter 

Chrome-copper mordant. 

Bichromate of soda 2 gms. 

Copper sulphate 0.25 gms. 

Cream of tartar 1.0 gms. 

Water 1 liter 

Copper-iron mordant. 

Copper sulphate 2 gms. 

Ferrous sulphate 2 gms. 

(Acetic acid 50% 2 gms.) 

Water 1 liter 



The killed skins are immersed in the mordanting solution, 
and allowed to remain the required length of time. They 
are then thoroughly rinsed to remove any excess of the 
mordant, and are hydro-extracted. Under no circumstances 
should mordanted skins be permitted to dry, for they would 
be unfit for use again. 

The dyebath is next prepared by dissolving the necessary 
quantity of the dye, varying from 0.1 gm. to 10 gms. per 
liter. Then if the solution must be neutralized, the am- 
monia is added and the temperature of the bath is brought 
to 30-35° C. by the addition of cold water. This tempera- 
ture is maintained throughout the dyeing operation. To the 
solution is added the oxidizing agent. Ordinary commercial 

167 



FUR DRESSING AND FUR DYEING 

peroxide of hydrogen containing 3% by weight is the usual 
oxidizer, although perborates have been suggested, 15-20 
parts of peroxide of hydrogen for every part of dye are 
added, and the dye solution brought to the proper dilution. 
As soon as the dyebath is ready, the skins are entered, and 
worked for a short time to effect even penetration. They are 
then left in the dyebath for 2-12 hours or longer according 
to the depth of shade. After being satisfactorily dyed, the 
furs are rinsed thoroughly, hydro-extracted and dried and 
finished. Where the dye is to be applied by the brush 
to the tips of the hair, stronger dye solutions are used, 
the brushed skins being placed hair together and let lie for 
about 6 hours in order to permit the color to develop, after 
which the furs are dried and drum-cleaned. 

Some shades, particularly black, have a tendency to rub 
off slightly. In order to overcome this, the dyed furs, after 
rinsing, are treated with a cold solution of ^ part of 
copper sulphate per 1000 parts of water, for 3-4 hours, then 
without rinsing, hydro-extracted and dried. Furs which have 
been tipped are brushed with a 1-2% solution of copper 
sulphate and dried. Care must be taken in this after-treat- 
ment, for the use of too strong a solution of copper sulphate, 
or too prolonged action of such a solution will materially 
alter the shade of the dyed fur. 

A few typical formulas will serve to illustrate the general 
methods of employing the Oxidation Colors: 



Brown Sable Imitation on Unsheared Rabbit ' 

The skins are killed with soda, soured, and washed, then 
mordanted with 



Bichromate of soda 


2 grams 


Copper sulphate 


.25 grams 


Cream of tartar 


1 gram 


Water 


1 liter 



168 



OXIDATION COLORS 



for 24 hours. Then washed, and dyed for 24 hours with 
Fur Brown 2G ^ 3 grams 

Hydrogen peroxide 45 grams 

Water 1 liter 

Wash and dry the skins, then brush the tips with 
Fur Brown D ^ 20 grams 

Hydrogen peroxide 400 grams 
Water 1 liter 

Black on Sheared Muskrat 

The skins are killed with soda, soured, and washed, then 

chrome mordanted for 6 hours. Then they are dyed for 
6 hours with 

Rodol P 1.5 grams 

Pyrogallic acid .7 grams 

Ammonia 2.0 grams 

Hydrogen peroxide 45 grams 

Water 1 liter 

The dyed skins are washed and dried, then tipped with 
Rodol D 20 grams 

Rodol DB 2 grams 

Hydrogen peroxide 450 grams 

Water 1 liter 

Brown on Thibet Sheep Skin 

The killed skins are mordanted for 6 hours with a chrome 
mordant, then dyed for 6 hours with 



Ursol P 


1 gram 


Pyrogallic acid 


1 gram 


Ammonia 


2 grams 


Hydrogen peroxide 


40 grams 


Water 


1 liter 



^ Inasmuch as most manufacturers use the same letters to designate the 
various dyes, any equivalent brand of fur dj'e may be used in place of those 
here mentioned. 

169 



FUR DRESSING AND FUR DYEING 

It is also possible to combine dyeings with the Oxidation 
Colors with Vegetable dyeings, or with Aniline Black. For 
example, if it be desired to produce an imitation skunk 
on a raccoon, and an exceptionally fast and intense and 
lustrous black on the tips of the hair, the skins are dyed in 
the bath with the Oxidation dyes, and the tips of the hair 
are brushed with a mixture such as described under Vege- 
table Colors for the production of French seal, as follows : 

Imitation Skunk on Racoon 

c 
The skins are killed with caustic soda, soured and washed, 

then mordanted with an iron-copper mordant as described, 

and then dyed with 



Fur Grey R 


3 grams 


Ammonia 


2 grams 


Peroxide of hydrogen 


45 grams 


Water 


1 liter 



After washing and drying, the dyed skms are brushed over 
with a mixture such as used for dyeing French seal with 
Vegetable Colors. 

In a similar manner, the Oxidation Colors may be used 
to give a base color to furs dyed by the Aniline Black 
process. 

It is apparent from these few illustrations that a great 
variety of shades can be produced, and the dyeing of imita- 
tions of the better class of furs on cheaper skins is a com- 
paratively simple matter, after an understanding of the 
nature of the dyes has been obtained, and a certain amount 
of skill acquired in working with these dyes. 



170 



CHAPTER XVI 
FUR DYEING 

Coal Tar Dyes 

IN addition to the Aniline Blacks and the Oxidation 
Colors already discussed there are certain of the syn- 
thetic coal tar dyes such as are generally used in the 
dyeing of textiles, which can also be applied on furs. There 
are several classes of these dyes, varying somewhat in their 
nature, and consequently in their manner of application; 
in the main they produce bright shades, such as are but 
seldom used on furs, yet which may occasionally serve for 
the production of novel effects. Basic, acid and chrome 
colors are the types which can be employed. 

Basic colors possess great fullness and tinctorial strength, 
but have a tendency to rub off. and the tips of the hair 
take a darker shade with these dyes than the rest of the 
hair. The addition of acetic acid and Glauber's salt to the 
dyebath will result in a more uniform dyeing. On account 
of the comparatively poor fastness to rubbing and washing, 
basic dyes are used only for dyeing furs which are intended 
for cheap carpet rugs, such as sheep and goat. They may 
also find use in the production of light fancy shades on 
other white furs. The procedure is usually as follows: The 
furs are killed in the customary manner with soap and soda 
or ammonia, or if this is insufficient, with milk of lime. A 
soap-bath is then prepared containing 2.5-6 grams of olive- 
oil soap per liter of water. The temperature of the bath is 
brought to 40° C. To this is added the solution of the dye- 
stuffs, prepared by mixing the required color or colors with 
a little acetic acid to a paste, and then pouring boiling water 

171 



FUR DRESSING AND FUR DYEING 

on the mixture until dissolved. Undissolved particles or 
foreign matter are removed by passing this solution through 
a cotton cloth or sieve, and the clear solution then mixed 
with the soap-bath. The well-washed skins are then 
entered into the dyebath and immersed for about half an 
hour, or until the desired depth of shade is obtained. They 
are then removed, pressed or hydro-extracted and dried. 
For the production of light shades, the following dyes may 
be used: 

For cream, light sulphur-yellow, maize, salmon, etc. 

Combinations of 
Thioflavine 
Rhodamine B 
Irisamine G 

For greenish-yellows 

Combinations of 
Thioflavine 
Victoria Blue B 

For light pink 

Rhodamine B 

Irisamine 

Rose Bengal Extra N 

For purple 

Methyl Violet 3B-6B 
Crystal Violet 

For sky-blue 

Victoria Blue B 

For white 

Victoria Blue B (Milk-white) 
Methyl Violet 3B-6B 
Crystal Violet (Ivory-white) 

172 



COAL TAR DYES 



To produce very delicate shades, the moist dyed skins are 
subjected to a sulphur bleach overnight, to lighten the color, 
then rinsed, and dried. Full, brilliant shades may be ob- 
tained by dyeing in a bath of 40° C, acidulated with 2-3 
grams of acetic acid per liter of solution, the following dye- 
stuffs being suitable: 

For yellow to orange 

Thioflavine 

Paraphosphine 

Rhodamine 

Safranine 

New Magenta 

For pink 

Rhodamine B 

Rose Bengal Extra N 

For light red 

Safranines 

For bordeaux and red 

Magenta 
New Magenta 
Russian Red 
Cerise 



For violet 



For blue 



Methyl Violet 6B-4R 
Crystal Violet 5B 



Victoria Blue B 
Methylene Blue BB 
New Methylene Blue N 

173 



FUR DRESSING AND FUR DYF^ING 

For green 

Malachite Green Crystals 

Brilliant Green Crystals, or combinations of 

Thioflavine 

Diamond Phosphine 

Victoria Blue B 

For brown 

Chrysoidines 
Bismarck Browns 

In dyeing skins with harder hair than that of sheep or goat, 
mere killing is insufficient to render the hair capable of 
taking up the dye. The skins are therefore immersed before 
dyeing, in a cold, weak solution of chloride of lime, the 
affinity of the hair for the dye being thereby greatly in- 
creased. 

Acid dyes are employed when a greater fastness is re- 
quired than can be obtained with the basic colors. Sul- 
phuric acid in a quantity equal to half the weight of the 
dyestuffs used, together with four times that quantity of 
Glauber's salt is added to the dyebath. Formic acid may 
be used in place of the sulphuric acid, very good results 
being obtained. The skins are immersed in the dyebath, 
and worked until thoroughly soaked with the dye liquor, 
and then allowed to remain until the proper depth of shade 
is attained, or overnight. The temperature of the solution 
is about 40° C., and only very light shades can be produced 
in this manner. In 1900 and again in 1914, the Cassella Co., 
a large German manufacturer of dyestuffs, obtained patents 
for processes enabling the dyeing of furs in hot solution 
with the acid dyes. The method required that the skins 
be chrome-tanned in order to render them resistant to the 
action of hot solutions, the addition of a small amount of 
formaldehyde to the chrome solution increasing this effect. 
The skins are then treated with a solution of chloride of 

174 



COAL TAR DYES 



lime in order to increase the affinity of the hair for the dye- 
stuffs. The method as it is now practised is as follows: 
The skins which have been cleaned and washed are chrome 
tanned by the method as described in the chapter on Tan- 
ning Methods, 60 grams of formaldehyde being added to 
every 10 liters of the chrome solution. After proper tanning 
the skins are rinsed, and while still moist they are subjected 
to a treatment with chloride of lime. They are first im- 
mersed for 15 minutes in a cold bath containing 120 grams 
of hydrochloric acid 32-36° Twaddell per 10 liters of water, 
then without rinsing, they are entered into a bath made up 
by adding gradually in four portions the clear solution of 
2-4 grams of the chloride of lime per 10 liters of water. 
After working for an hour, the skins are removed and 
entered again into the acid solution, in which they are 
worked for another 15 minutes. In order to neutralize and 
remove the last traces of the chloride of lime from the 
furs, they are rinsed in a luke-warm bath containing 1-2 
grams of sodium thiosulphate, or hyposulphite of soda, in 
10 liters of water. The skins are then rinsed again, and 
hydro-extracted, or pressed, and are ready for dyeing. The 
dyebath is prepared with the required quantity of dye, to 
which is added 10-20% Glauber's salt and 2-5% acetic 
acid (both calculated on the weight of the skins). The 
skins are entered at 20° C, then after three-quarters of an 
hour to 40° C, and then after another hour slowly to 
50-55° C. For blacks, the temperature is raised as high 
as 65° C. After dyeing the skins are treated with a solution 
containing per 10 liters 

90-120 grams of olive-oil soap 
12-25 grams olive oil 
12 grams ammonia 
for 15 minutes, then hydro-extracted and dried, without 
further rinsing. 



175 



FUR DRESSING AND FUR DYEING 



For this method of dyeing, the following dyes may 
be used: 



For yellow and orange 
Fast Yellow S 
Acid Yellows 
Naphthol Yellow S 
Tropaeoline 
Orange GG, R, II, IV 

For blue 
Cyanole FF 
Azo Wool Blue 
Naphthol Blue R 
Formyl Blue B 

For brown, combinations of 
Fast Yellow S 

Acid Yellows 

Tropaeoline DD 

Orange GG 

Lanafuchsine 

Indigo Blue N 

Cyanole B 

Fast Acid Green BN 



For reds 
Acid Reds 
Lanafuchsine 
Azo Orseille 

For violet 
Azo Wool Violet 
Acid Violets 

For green 
Naphthol Green B 
Fast Acid Green 
Cyanole Green 

For black 

Naphthylamine Blacks 
Naphthol Blacks 
Naphthol Blue-black 

For grey 

Silver Grey N 

Dyed with the addition of 
i-1% of alum 



The chrome colors are dyed on furs when very fast 
shades are desired, all the fancy colors being produced in 
this manner, but for black, only the acid dyes are suitable. 
The preparation of the skin is exactly the same as for the 
acid colors, except that the treatment with chloride of lime 
may be omitted, although for very full shades it is desirable. 
The dyeing is carried out as follows: The dyebath is pre- 
pared with the requisite amount of the desired dyestuff, 
which is previously dissolved, and to this is added a solu- 
tion of sodium bichromate, the amount of this substance 
being half the weight of the dye. The solution is heated 



176 



COAL TAR DYES 



and the skins entered and dyed for 1-2 hours at 70-80° C. 
Then the dyebath is exhausted by the addition oi ^% 
acetic acid, the skins being worked for another half hour, 
then rinsed, hydro-extracted and dried. Any of the one- 
bath chrome, or after-chrome colors may be used for this 
method. 

Recently methods have been patented for the dyeing of 
furs by means of the vat colors. Vat dyes are among the 
fastest coloring matters ever produced, and their appli- 
cation on furs would be a great advantage, if suitable shades 
could be obtained. The general process for dyeing with 
vat colors, consists in reducing the dye, which is usually 
very insoluble, into a soluble " leuco " compound, by means 
of hydrosulphites in the presence of alkalies. The leuco 
compound is not a dye itself, but when the fibre absorbs it, 
and is then exposed to the air, the leuco compound is re- 
oxidized to its original insoluble form, which remains fast 
and permanent. The use of strong alkalies in vat dyeing 
has hitherto been a great obstacle in the use of these dye- 
stuffs, but in 1917, the Farbwerke Hoechst, a large German 
dyeworks, patented a process as follows: "A process for 
dyeing furs with vat colors. The dyeing is done in solu- 
tions of the vat dyes (after the addition of gelatine or some 
other protective colloid), which are rendered neutral or 
only slightly alkaline with ammonia, by neutralizing the 
caustic soda of the solution of the leuco compound of the 
vat dyes by the addition of ammonium salts, or suitable 
acids. The dyeings thus obtained are uniform and fast, 
the leather is dyed to only a slight degree, and shows no 
deleterious effects of the dyebath on the tannage." As a 
practical application of this process, another patent was 
taken out by the same company, also in 1917, as follows: 
" A process for producing fast blacks on furs, consisting of 
dyeing a ground color with appropriate vat dyes in a hydro- 
sulphite vat, and after oxidation in air, topping with an 
Anihne or Diphenyl black. The dyeings obtained by the 

177 



FUR DRESSING AND FUR DYEING 

combination of vat dyes which are fast to oxidizing agents, 
with an oxidation black, have an appearance matching that 
of logwood black in beauty; and with a dark-blue to blue- 
black under-color, and a full, deep black top color, can- 
not be distinguished from logwood. These dyeings also 
have the advantage of being faster to light than logwood or 
other blacks." 

While these processes undoubtedly have many meritorious 
qualities which make them interesting, they do not seem as 
yet, to have attained any great practical application. 
However, it is a field of fur dyeing which is worth while 
developing, and with certain necessary improvements in 
these processes, the vat dyes may yet supersede partially 
some of the other methods of dyeing furs. 



178 



CHAPTER XVII 
BLEACHING OF FURS 

BLEACHING is for the purpose of lightening the 
color of furs, and is most generally applied to white- 
haired skins such as white fox, ermine, and 
occasionally white lambs of all kinds, and white bears. 
Among such furs, pelts of a naturally pure white tone are 
relatively scarce, while in the majority of cases the color 
ranges from a pale creamy white to a decidedly yellowish 
shade. Colors which vary from the pure white detract con- 
siderably from the attractiveness and consequent value of 
the fur, and indeed, some pelts are so far off shade that 
they can only be used when dyed a darker color. Most 
white skins which are but slightly inferior in color can be 
brought to a pure white by bleaching, and they can then 
be used natural. Some pelts, on the other hand, are par- 
ticularly resistant to the action of bleaching agents and 
cannot be sufficiently decolorized to render them suitable 
for use natural, so these are also dyed. For the production 
of certain delicate or fancy dyed shades on white furs, it is 
often necessar}^ to bleach the skins in order to be able to 
obtain pure tones. Such instances are not very common, 
however. Occasionally dark furs, such as beaver, are 
bleached on the tips of the hair, a golden shade being 
obtained thereby, which at one tune was quite popular, but 
recently such effects have not been in vogue. 

In the bleaching of furs, two steps may be distinguished, 
first degreasing, and second, bleaching proper. In the pre- 
liminary operations of fur dressing, the furs are treated with 
soap or weak alkalies to cleanse them and to remove excess 
oil from the hair. During the various processes and raa- 

179 



FUR DRESSING AND FUR DYEING 

nipulations, the hair, especially on white skins, may be- 
come soiled or somewhat greasy again, so it is advisable to 
repeat the cleaning process. This should in every case be 
as light as possible, using a weak solution of soap for the 
softer and cleaner pelts, or dilute solutions of ammonium 
carbonate or soda ash for the more greasy-haired skins. 
The skins are then thoroughly rinsed to remove all traces 
of the degreasing material. This step is very essential in 
order to obtain uniform bleaching. 

Broadly speaking, there are two general methods which 
can be used in bleaching furs, one involving the use of what 
are known as reducing agents, and the other employing 
oxidizing substances. 

Among reducing agents which can be used for bleaching 
furs are sulphurous acid, and its salts such as sodium bisul- 
phite and sodium sulphite; hydrosulphites, and derivatives. 

1. Sulphurous acid. — When sulphur is burned, sulphur 
dioxide gas is formed. In the presence of moisture, or when 
dissolved in water, this gas forms sulphurous acid, which is 
one of the most commonly used bleaching chemicals for all 
sorts of materials, and is very effective for decolorizing furs. 
The procedure usually followed is to hang up the moistened 
skins on wooden rods in a more or less cubical chamber 
made of stone or brick, and lined with wood or lead. No 
other metals may be used, because they are quickly cor- 
roded by the sulphurous acid. The requisite quantity of 
sulphur is placed in a pot in the bleaching chamber, and 
then ignited, after which the doors are shut tight. The 
fumes of the burning sulphur in contact with the moist hair 
readily exert their bleaching action on the furs, and the 
operation is allowed to proceed for six or eight hours, or 
overnight. Then by means of fans or other devices, the air 
filled with sulphur dioxide gas is withdrawn from the 
chamber, and replaced by fresh air. The door is opened, 
the skins removed, exposed to the air for a time, then 
rinsed, and finally dried and finished. Sometimes one 

180 



BLEACHING OF FURS 



operation is not enough to sufficiently bleach the hair, so 
the process is repeated. Sulphur dioxide gas can now be 
obtained compressed in cylinders, which are more conven- 
ient to handle than burning sulphur. The flow of gas which 
is introduced into the bleaching chamber by means of a 
nozzle attached to the cylinder, can be regulated, and the 
bleaching thus retarded or accelerated. 

2. Sodium bisulphite and sodium sulphite. — These salts 
of sulphurous acid are effective in their bleaching action 
only when in solution in the presence of acids. The acids 
liberate sulphurous acid from the salts, so this method is 
virtually the same as 1. Instead of using the salts of sul- 
phurous acid, sulphur dioxide may be dissolved in water, 
and the solution used for bleaching by immersing the furs 
in it. This procedure, while consuming somewhat less time 
than the chamber process, is more likely to affect the 
leather, which would have to be retanned. The principle 
is the same as that involved in method 1. 

3. Hydrosulphites and derivatives. — The bleaching 
agent can be prepared by adding zinc dust to commercial 
bisulphite of soda dissolved in about four times its weight 
of water until no more reaction is evident. Milk of lime is 
then added to precipitate the zinc, and the clear superna- 
tant liquid of 1.5°-5° Tw. is used for bleaching. The skins 
are immersed for 12-24 hours, taken out, washed and 
finished. Instead of preparing the hydrosulphite, the com- 
mercial products may be used with greater convenience, a 
solution containing 1-4% of the hydrosulphite powder be- 
ing used, and the skins treated in this until satisfactorily 
bleached. 

The bleaching action of sulphurous acid and hydrosul- 
phite is supposed to be due to the reduction of the coloring 
matter of the hair to a colorless compound; or possibly to 
the formation of a colorless compound of the bleaching 
material with the pigment. The former seems the more 
probable explanation, because the change is not a perma- 

ISl 



FUR DRESSING AND FUR DYEING 

nent one, the original natural color returning after a long 
exposure of the bleached fur to air and light. However, 
the results are sufficiently enduring to satisfy the require- 
ments of the trade in the class of furs on which these meth- 
ods of bleaching are used. 

Bleaching chemicals with an oxidizing action generally 
used for decolorizing furs are hydrogen peroxide and per- 
oxides; occasionally hypochlorites and permanganates are 
also used. 

1. Hydrogen peroxide. — Hydrogen peroxide is usually 
employed for bleaching in the form of its 3% solution, to 
which is added about 20 cubic centimeters of ammonia 
per liter. The ammonia serves partially to neutralize the 
acid which commercial peroxide generally contains, and also 
to facilitate the bleaching action. The thoroughly de- 
greased skins are immersed in the solution until the hair is 
completely wetted by it, are then removed, and evenly 
pressed or hydro-extracted, after which the pelts are hung 
up to dry in the air. As the hair becomes drier, the con- 
centration of the peroxide becomes greater, and conse- 
quently the bleaching action is stronger. Where there is 
a likelihood of the leather being affected by the bleaching 
solution, the ammoniacal peroxide may be applied to the 
hair with a fine sponge or brush until sufficiently wetted, 
and then hanging the skins up to dry. Repetition of the 
process is sometimes necessary to obtain pure white, but the 
results are always excellent. 

2. Peroxides. — The most important of these is sodium 
peroxide, which comes on the market as a yellowish-white 
powder, which must be kept dry, and away from any in- 
flammable material, as fires have been caused by the con- 
tact of the peroxide with such substances. When dissolved 
in water, it is equivalent to a strongly alkaline solution of 
peroxide of hydrogen. 



182 



BLEACHING OF FURS 



Na.,0, + 


2 H2O : 


= H2O, + 


2 NaOH 


sodium 


water 


peroxide 


caustic 


peroxide 




of 
hydrogen 


soda 



When dissolved in acid, the alkali is neutralized, and a 
neutral solution of peroxide of hydrogen and a salt is ob- 
tained, and this method is used to obtain peroxide of 

Na^O^ + 



H3S04 = 


= H.O, 


+ Na,S04 


sulfuric 




sodium sulphate 


acid 







hydrogen cheaply. 3 parts of sodium peroxide are slowly 
dissolved in a cold 1% solution of 4 parts of sulphuric acid, 
stirring during the addition, and making the resulting solu- 
tion neutral to litmus paper, acid or more sodium peroxide 
being added as needed. There is then added 3-6 parts of a 
solution of silicate of soda of 90° Tw. The skins are im- 
mersed until properly bleached, taken out, passed through 
a weak acid solution, then washed and finished. This 
method generally requires the leather to be retanned after 
bleaching. Another process, which involves the use of 
peroxides, but which is not commonly practised, consists in 
rubbing the hair with a pasty mixture of equal parts of 
water, barium dioxide, and silicate of soda, hanging up the 
skins to dry, and then beating and brushing the hair. 

3. Permanganates. — The only member of this group 
that finds practical application for bleaching purposes is 
potassium permanganate. The skins are immersed in 
a 0.1% solution of the crystals of potassium permanganate, 
until the hair acquires a deep brown color. They are then 
removed, rinsed, and entered into a second bath containing 
sulphurous acid in solution, prepared by acidifying a solu- 
tion of sodium bisulphite. The skins are then worked in 
this until fully bleached. It is the permanganate which 
does the bleaching, the sulphurous acid being for the pur- 

183 



FUR DRESSING AND FUR DYEING 

pose of dissolving the brown compound of manganese 
formed on the hair, 

4. Hypochlorites. — Chloride of lime and sodium hypo- 
chlorite, which is prepared from the former, are the chief 
chemicals of this type used for bleaching. The skins are 
entered into a weak solution of the hypochlorite, and left 
until the hair is decolorized ; then after removing, they are 
passed through a dilute acid, and subsequently through a 
weak solution of sodium thiosulphate in order to remove all 
traces of the hypochlorite. This method causes the hair to 
acquire a harsh feel, and the yellow color is never entirely 
eliminated. The hair, however, possesses a great affinity 
for certain types of dyestuffs, and it is only when these 
particular classes of dyes are to be applied to the furs, that 
the hypochlorite bleach is used. (See dyeing with Acid 
colors). 

The various oxidation methods of bleaching are supposed 
to change the coloring matter of the hair into an entirely 
different and colorless compound which cannot return to its 
original form. The bleach is therefore permanent. 

In common practise, the sulphurous acid, and the perox- 
ide of hydrogen methods are the two chiefly employed in 
bleaching processes. Sulphurous acid is used to bleach the 
cheaper kinds of furs, while peroxide of hydrogen is applied 
to the finer furs. 

Whichever process is used, it is customary to give the 
bleached skins a subsequent " blueing," by passing them 
through a very weak solution of a blue or violet dye, such 
as indigo-carmine, crystal violet, alkali blue or ultramarine. 
The furs are then dried and finished off as usual. In drum 
cleaning white furs, gypsum or white sand, or sometimes 
even talc are used with the sawdust, or occasionally alone 
without the sawdust. 



184 



BIBLIOGRAPHY . 

Allen " Commercial Organic Analysis " 

Armour, B. R. " Fur Dressing and Dyeing " 1919 

Color Trade Journal, Vol. 1, p. 51-53 

Jour. Amer. Leather Chemists' Assn., Vol. 13, p. 63-69. 

Belden, A. L. " Fur Trade in America " 1917 

Beltzer, F. J. G. " Industrie des Foils et Fourrures, etc." 1912 

Revue Generale des Matieres Colorantes, Vol. 12, 1908 

Bennett, H. G. " Manufacture of Leather " 1910 

Bertram, P. Deutsche Fiirber-Zeitung 1895-96 Heft 17, p. 266 

Bird, F. J. " American Practical Dyers' Companion " p. 241-245 

Boerner, H. Kunststoffe, 1912 p. 223 

Brevoort, H. L. " Fur Fibres as shown in the Microscope " 1886 

Buclier, B. '' Geschichte der technischen Kiinste " 1875-1893 

Cubaeus, P. " Das Ganze der Kiirschnerei " 1912 

Davis, C. T. " Manufacture of Leather " 

Erdmann, E. Deutsche Fiirber-Zeitung 1894-95 Heft 21, p. 337 

Zeitschrift fiir angewandte Chemie, 1895, Heft 14 

Zeitschrift fiir angewandte Chemie, Heft 35, 1905 

■ ■ Berichte, 1904, 37, p. 2776, 2906 

Farrell, F. J. "Dyeing and Cleaning" 1912 

Fougerat, L. " La Pelleterie dans I'antiquite, la prehistoire, etc." 

Fleming, L. "Practical Tanning" 1916 

Gardner, W. M. "Wool Dyeing" 1896 

Grandmougin, E. Zeitschrift fiir Farben-Industrie, 1906, 5, p. 141 

Gruene, E. Deutsche Fiirber-Zeitung, 1895-96 Heft 13, p. 197 

Halle " Werkstatte der heutigen Kiinste," 1762, Vol. 2, p. 317 

Hartwig, O. L. " Sprengler's Kiinste und Handwerke," 1782 

Hausman, L. A. Scientific Monthly, Jan. 1920; March, 1921 

Natural History, Vol. 20, 4, 1920 

American Journal of Anatomj^ Sept. 1920 

American Naturalist, Nov.-Dec. 1920 

Hayes, A. H. National Cleaner and Dyer, Nov. 1920, p. 55-57 

Jacobson, " Schauplatz der Zeugmanufacturen " p. 493 

Jones, J. W. " Fur Farming in Canada " 1913 

Knecht, Rawson & Loewenthal " Manual of Dyeing" 1916 

Kobert, R. " Beitrage zur Geschichte des Gerben und der Astringentien " 

1917 
Koenig, F. Zeitschrift fiir angewandte Chemie, 1914, Vol. 1, p. 529 
Lamb, M. C. "Dressing of Leather" 1908 

185 



BIBLIOGRAPHY 



Jour. Soc. Dyers & Colourists 1913. 29, p. 160-165 



Lamb, J. W. Jour. Soc. Dyers & Colourists Dec. 1905, p. 323 

Larish & Schmid "Das Kuerschner Handwerk " 1-3 

Laut, A. C. " The Fur Trade of America " 1921 

Martin, G. '' Industrial Organic Chemistry " 

Lightfoot, J. " The Chemical History & Progress of Aniline Black " 1871 

Mairet, E. M. " A Book on Vegetable Dyes " 1916 

Matthews, J. M. " Application of Dyestuffs " 1920 

Mayer, A. " Die Farberei in der Werkstiitte des Kiirschners " 

Mierzinski, S. " Die Gerb und Farbstoffextrakte " 

Noelting & Lehne " Anilin-Schwarz " 1904 

Perkins & Everest " Natural Organic Coloring Matters " 1918 

Petersen, M. ''The Fur Traders & Fur-Bearing Animals" 1920 

Poland, H. " Fur-Bearing Animals in Nature and Commerce " 

Proctor, H. " Leather Industries Laboratory Book " 

" Tanning " 

" Making of Leather " 

Schlottauer, E. Deutsche Farber-Zeitung 1911, Heft 20, p. 397 

Deutscher Farber-Kalender 1911, p. 65 

Leipziger Farber-Zeitung 1909, p. 441 

Schmidt, C. H. " Handbuch der Weissgerberei " 
Setlik, B. Deutsche FUrber-Zeitung 1901. p. 213 

Smith, R. W. Color Trade Journal Vol. 3, Sept. 1918, p. 304-310 

Textile Recorder, Vol. 36, p. 292-293, Dec. 1918 

Revue Generale des Matieres Colorantes, Vol. 23, p. 32-36 

Stevenson, C. H. " U. S. Fish Commission Report 1902-1903, Bulletin 

No. 537 
Stickelberger, E. " Geschichte der Gerberei " 1915 
Strasser " Chemische Farberei der Rauchwaren " 1879 
Ullmann " Enzyklopedie der technischen Chemie " 
Villon, A. M. " Traite pratique de la fabrication des cuirs, etc." 1900 
Werner, H. " Die Kiirschnerkunst " 1914 

" Das Farben der Rauchwaren " 1914 

Whittaker, C. M. " Dyeing with Coal Tar Dyes " 1919 
Wiener, F. " Weissgerberei " 1877 

Witt-Lehman '' Chemische Technologie der Gespinst-Fasern " 1910 
Zeidler, H. " Die moderne Lederfabrikation " 1914 



186 



INDEX 



Acetate, aluminum, IIS 

chromium, 120 

copper, 120 

ferrous, 119 

lead, 126 

Acetic acid, 112 
Acid dyes, 174 

Acids, action of, on hair, 29 

on skin, 26 

After-treatment with copper, 168 
Alaska fox imitations, 143 
Alkaline aluminum mordants, 122 

chromium mordants, 123 

iron mordants, 123 

Alum, 32, 53, 118 

chrome, 57 

chrome tans, 64 

tans, 54, 56 

Aluminum acetate, 118 
■ mordants, 118 

sulphate, 53, 118 

Ammonia, 110 
Ammonium sulphide, 126 
Aniline black, 144 

by dip process, 154 

chemistry, 145 

Green's process for, 152 

nature of, 144 

One-bath, 149 

Oxidation, 150 

■ processes, 149 

ungreenable, 148 

Aniline oil, 145 
Astrachan 5, 7, 12 

Bacteria, 51 
Badger, 7 
Ball-drum, 62 
Bandrowski's base, 164 
Basic dyes, 171 
Beam, 38 
Beaming, 38 
Bear, black, 5, 7 

brown, 5, 8 



white, 8 

bleaching of, 179 

Beating furs, 79 

Beaver, 5, 8, 25, 83, 94 

Beechwood ashes, 108 

Bichromate of soda, 121, 147 

Black, aniline, 144 

by Green's process, 

chemistry of, 145 
nature of, 144 
One-bath, 149 
Oxidation, 150 

ungreenable, 148 

Black, diphenyl, 152 

logwood, 139 

on Chinese goats, 141 

on lambs, 141 

on raccoon, 130 . 

on skunk, 130 

on wolf, 130 

Bleaching of furs, 179 
Blending, 91, 104 
Blue-grey on white furs, 142 
Blueing," 184 

Blue salt, 120 

vitriol, 119 

Borax, 39, 58 
Brasilein, 135 
Brasilin, 135 
Brazilwood, 135 

Bright shades on furs, 171 
Broadtail, 8, 12 

dyeing of, 139 

Brown on Thibet sheep, 169 

with natural dyes, 142 

Brush process, 98 

Brushes used in dyeing, 100 

Butter, 60, 63 

Cage, 80 
Cageing, SO 
Campeachy wood, 133 
Caracul, 8, 12 

dressing of, 53 



152 



187 



INDEX 



Caracul, dyeing of, 140 
Carnivorous animals, furs of, 37 
Cased skins, 3(5 
Castor oil, 60, 03 
Cat, civet, 5, S 

house, S 

Caustic soda, 44, 110. 113 
Centrifugal machine, 40 
Chamber drying. 73 
Chamois dressing, 31 

tan, 49,' oS, 61 

Characteristics of tans, 65 
Chestnut extract, 133 
Chinchilla, 5, 6, 8. 94 

blending of, 91, 104 

Chinchillone, 9 

China goat, black 'on, 141 
Chlorates, 147 
Chloride of lime, 174 

bleach, 1S4 

Cln-ome acetate, 120 

alum, 57, 120 

colors, 176 

copper mordant, 167 

formaldehyde tan, 64 

tans, 57, 174 

Chromimn mordants, 120, 166 

- — — alkaline, 123 

salts in tanning, 53 

Cleaning pelts, 40 

Coal tar colors, 171 
Cocoa nut oil, 60 
Cod-liver oil, 60 
Collagen, 25 
Colloidal solutions, 4S 
Combination tans, 49, 64 
Conveying dyed skins, 104 
Conveyor drying. 73 
Copper acetate. 119 

mordants, 119, 166 

salts, 109 

after-treatment with, 16S 

sulphate, 119 

Copperas, 119 
Copper-iron mordant, 167 
Coriin, 21 

Corium, 21 
Cortex, 23 

Cottonseed oil, 60, 63 
Cuba wood, 134 
Cutch, gambler, 65, 135 
Cuticle, 23 



Davy, Sir Humphrey, 47 

Degreasing furs, 179 

Diphenyl black, 152 

Dip process, 98 

Dressing of lambs, 52 

rabbits, 54 

moles, 54 

Drum, 80 

Drum-cleaning, 105 

Drumming, 76 

Drying-oils, 60 

Drying skins, 71 

Durability of furs, 5 

Dyeing furs at higher temperatures, 
174 

Dyeing of imitations, 93 

novelty shades, 92 
with aniline black, 144 
coal tar colors, 171 
mineral colors, 125 
oxidation colors, 155 

vegetable colors, 128 

Egg-yolk, 63 
Emeraldine, 145 
Enzymes, 51 
Epidermis, 21 
Erdmann, 155 
Ermine, 5, 9 

bleaching of, 179 

Fahrion, 48 
Fat-glands, 21 
Fats, animal, 59 
Fermentation, 51 
Ferrous acetate, 119 
Ferrous sulphate, 119 
Finishing dyed furs, 104 
Fisher, 9 
Fitch, 9, 94 
Flat skins, 36 
Fleshing, 41 

knife, 38, 42 

machines, 42 

Flesh side, 22, 37 
Formaldehyde, 63 
chrome tan, 64 

tans, 49, 63 

Formic acid, 44, 50 

as soaking agent, 39 

Fox, black on, 140 



188 



INDEX 



blue, 9 
cross, 4, 10 
grey, 10 
kit, 10 
red, 4, 5, 10 

dyed imitation silver fox, 
137 

silver, 4, 10 

imitations, 137, 143 

white, 11, 94 

bleaching of, 179 

French seal dye, 138, 144 
Furamine dyes, 162 

Fur beating machine, 80 
Fur dressing, 30 
Fur dyeing, 91 

difficulties of, 95 

with aniline black, 144 

with coal tar colors, 171 

with mineral colors, 125 

with oxidation colors, 155 

with vegetable colors, 128 

Fur-hair, 24 
Furriers' guilds, 34, 90 
Furrol dyes, 166 
Furs, colors of, 3 

description of, 7 

durability of, 5 

of carnivorous animals, 37 

of herbivorous animals, 37 

quality of, 3, 4 

uses of, 1 

valuation of, 6 

Aveight of, 5 

Fustic, 134 

— — • shades with, 135 

Gallnuts, 128, 132 
Gainbier cutch, 65, 135 
Gelatine, 1, 25, 47, 48 
Genet, 5 
Glycerine, 63 
Goat, 5, 11 

logwood black on, 141 

Green's process for aniline black, 152 
Grey-Vjlue on white furs, 142 
Ground water, 87 

Guard-hair, 24 

Guilds, furriers', 34, 90 

Hair, 22 

action of acids on, 27 



action of alkalies on, 28 

action of salts on, 28 

Hamster, 3, 11 
Hardness of water, 87 
Hare, 5, 11, 94 

black on, 140 

blue-grey on, 142 

lynx dye on, 1?6 

stone marten imitation on, 126 

Hematein, 133 
Hematoxyhn, 133 
Herbivorous animals, furs of, 37 
Hudson seal, 144 
Hydro-extraction, 40 
Hydrogen peroxide, 168 

bleaching with, 182 

Hydrosulphite bleach, 181 
Hypochlorites, 184 

Imitations, dyeing of, 93 
Iron mordants, 119, 167 
Iron pyrolignite, 119 
Iron salts in tanning, 53 
Iron tan, 58 
Iron vitriol, 119 

Kangaroo, 12 
Keratin, 25 
Kicker, 61 
Killing, 98, 106 
■ — — ■ formulas, 108 

nature of, 107 

purpose of, 106 

by brush process. 111 

by dip process. 111 

with caustic soda, 113 

■ with lime, 112 

with soda, 112 

Knapp, 46, 57 
Knife, beaming, 38 
— shaving, 38 

fleshing, 38 

Kolinsky, 5, 12 
Krimmer, 5, 12, 13 

Lactic acid, 44, 51 

Lactic acid fermentation, 50 

Lambs, 12 

dressing of, 50, 53 

dyeing of, 92, 140, 141, 142 

Lard, 60 

Lead, acetate, 126 



189 



INDEX 



Lead sulphide dye, 126 
Leather, definition of, 48 

dressing of, 30 

Leopard, 5, 13, 94 

tanning of, 43 

Lima wood, 135 
Lime, 108, 110, 112 
Linseed oil, 60 
Litharge, 109 

Loft drying, 72 
Logwood, 133 

blacks, 139 

shades with, 134 

Lynx, 5, 13 

imitation on rabbit and hare, 

126 

Luster of hair, 23 

Machines used in brush dyeing, 102 

• dip dyeing, 103 

Marmot, 14, 68, 94 
Marten, blending of, 91, 104 
Marten, baum, 5, 14 

stone, 5, 14 

- imitation, 126 

Medulla, 22 

Meunier, 46 
Mineral colors, 125 

oils, 59, 63 

■ tans, 49, 53 

Mink, 5, 14, 68, 94 
Mole, 5, 15 

• tanning of, 54 

Monkey, 15 
Mordanting, 98, 114 
Mordants, alkaline, 121 

aluminum, 118 

chrome-copper, 167 

— • chromium, 120, 166 

copper, 119, 166 

copper-iron, 167 

iron, 119, 167 

tin, 121 

Mucines, 25 

Muskrat, 5, 15, 68, 94 

imitation seal on, 144, 169 

Neatsfoot oil, 60, 63 
Neradol D., 64 
Nigraniline, 147 
Non-drying oils, 60, 63 
Novelty shades, dyeing of, 92 



Nutgalls, 33, 132 
Nutria, 5, 15, 94 

Oiling, 62, 77 
Oils, drying, 60 

non-drying, 50 

partially-drying, 60, 63 

OUve oil, 60 

One-bath aniline black, 149 
Opossum, 5, 15, 68 
— — black on, 140 

skunk imitation on, 138 

seal imitation on, 144 

Otter, River, 5, 16, 94 

- — — Sea, 5, 16 

Over-hair, 24 

Oxidation aniline black, 150 

— colors, 155 

shades with, 165 

Para-amido phenol, 153, 157 
Para-phenvlene diamine, 153, 157, 

162 
Partially-drying oils, 60, 63 
Pelage, 2 
Pelt, 2 

Pernambuco wood, 135 
Peroxide of hydrogen, 168, 182 
Peroxides, 182 
Persian Iamb, 5, 12 

dressing of, 50, 53 

dj'eing of, 139 

Physical theories of tanning, 47 
Pickle, 49 

Pigment granules, 23 
Pony, Russian, 5, 16 
Potassium permanganate as a dye, 
127 

— — as a bleach, 183 

Protective-hair, 24 
PyroUgnite of iron, 119 

Quercitron, 135 
Quinone di-imine, 163 

Rabbit, 6, 17, 94 

imitation seal on, 144 

lynx imitation on, 126 

• sable imitation on, 168 

stone marten imitation on, 126 

tanning of, 54, 65 

Raccoon, 6, 17 



190 



INDEX 



black on, 140 

skunk imitation on, 170 

Rain water, 86 

Red fox, dyed as silver fox, 137 
Redwood, 135 
Rodol colors, 165 
Russian tan, 51 

Sable, 6, 94 

American, 17 

blending of, 91, 104 

imitation on rabbit, 168 

Russian, 18 

Salammoniac, 109 
Salt, 32, 49 

-acid tan, 49 

water soak, 39 

Salts, neutral, 54 

basic, 54, 115 

Sawdust in drum-cleaning, 80 
"Schrot-beize," 50 

Seal, 6, 18, 94 

fur, 18 

dyeing of, 92, 144 

■ hair, 19 

imitation on muskrat, 138, 

169 

oil, 60 

Shearing, 82 

machine, 84 

Shrinking-point of skins, 66 

effect of chemicals on, 67 

Silver fox imitations, 137, 143 
Skin, 21 

action of acids on, 26 

action of alkalies on, 27 

Skunk, 6, 19, 94 

-imitation on opossum, 138 

on raccoon, 170 

Soaking sldns, 39 

Soda ash, 110, 112 

Sodium bichromate, 121, 166 

bisulphite, 127, 181 

chloride, 49 

peroxide, 182 

sulphite, 181 

Soft water, 87 
Softening skins, 38 
Souring, 113 
Squirrel, 6, 19 



Staking, 78 

Stannous chloride, 121 

Stiasny, 64 

Stone marten imitation, 126 

Stretching, 78 

machines, 78 

Sugar of lead, 126 
Sulphonated oils, 63 
Sulphuric acid, 49 
Sulphurous acid bleach, 180 
Sumach, 128, 133 

tanning with, 33 

Surface water, 87 
Sweat-glands, 22 

Tallow, 60 

Tanned furs, qualities of, 48 

Tanning methods, comparison of, 65 

Tannins, 32, 132 

Tiger, 19 

Top-hair, 24 

Train oils, 63 

Tramping machine, 61 

Turmeric, 136 

Under-hair, 24 
Under-wool, 24 

Ungreenable aniline black, 148 
Unhairing, 82 

machine, 83 

Ursol dyes, 157, 165 

Vanadium compounds, 147 
Vat dyes, 177 
Vegetable dyes, 128, 136 
oils, 59* 

tans, 49, 65 

Verdigris, 120 

Water, hard, 87 

soft, 87 

Whale oil, 60 

White fox, bleaching of, 179 
Wolf, 6, 19 
Wolverine, 6, 20 
Wombat, 20 
Wood dyes, 128 

Yellow wood, 134 



191 



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